Hoping this helps someone else out there that ran into the same problem. This seems to only affect macOS 10.12 Sierra; I was able to install the mods correctly on macOS 10.11 El Capitan without issue.

I downloaded and installed the Mac version of PS:T which is based on Wine and wrapped with Wineskin to appear as a native Mac app.

I followed the mod directions to get the game to the recommended configuration:
https: //www.gog.com/news/mod_spotlight_planescape_torment_mods_guide
http: //gaming.stackexchange.com/questions/166129/how-can-i-install-mods-on-the-mac-release-of-planescape-torment

[Note: This forum won't allow me to post links, so I have added spaces to my links to get past this restriction.]

The problem was: when I tried to install the fifth and final mod, "Qwinn's PS:T Tweak Pack" or Setup-PST-Tweak.exe, and I selected install on the "Stackable Rings, Charms, Bracelets, Scrolls" option, the mod installer would hang and use 100% CPU indefinitely.

The solution is: Update the wine engine in the Wineskin wrapper around PS:T. At the time of this writing, the GOG-14 version for Mac comes bundled with the WS9Wine1.7.35 engine and the latest available engine is WS9Wine1.9.24.

Instructions to update the wine engine:

1. Download and install Wineskin Winery: http: //wineskin.urgesoftware.com/tiki-index.php?page=Downloads
2. Launch Wineskin Winery and use the '+' button to open the Add Engine dialog.
3. Select engine WS9Wine1.9.24 from the popup menu, and click "Download and Install".

Wineskin Winery now has the WS9Wine1.9.24 engine available to it. Next we need to modify the Planescape: Torment application bundle to use this newer engine.

4. Locate the Planescape Torment app bundle in Finder. Right click > Show Package Contents.
5. Double click the Wineskin app (inside of the Planescape Torment app) to open the Wineskin settings.
6. Select "Advanced" to open the Wineskin Advanced settings.
7. Select the "Tools" tab in the Wineskin Advanced settings.
8. Click "Change Engine Used" to open the Choose Engine dialog.
9. Select the WS9Wine1.9.24 engine, which was installed via Wineskin Winery in step 3, and click OK.
10. Give it some time to update the engine, then close out of the Wineskin settings.

Now with the updated wine engine in the PS:T application bundle, all of the mods will install correctly on macOS 10.12 Sierra.

====================================

Also, if it's helpful to someone, here are the steps I used to install the game with all of the mods:

1. Download the PS:T installer package from GOG
2. Run PS:T installer package, select install location
3. [10.12 Sierra Only] Update wine engine, see instructions above.
4. Download the mod compliation pack: http: //www.mediafire.com/?3x7ne4elq16o4qo
5. Unzip pstmods.zip to pstmods/
6. Copy the contents of pstmods/ into Planescape Torment.app/drive_c/GOG Games/Planescape Torment/
7. Hold Alt and double click Planescape Torment.app to open Wineskin configuration

8. Select "Install Software", then "Choose Setup Executable"
9. Select Planescape Torment.app/drive_c/GOG Games/Planescape Torment/setup-widescreen.exe

a. 0: English
b. N: No readme
c. 1: Install widescreen mod for original Infinity Engine
d. 1440: X coordinate
e. 900: Y coordinate
f. Y: Update saved games
g. N: No support for multiple resolutions
h. Y: Confirmation
i. Lots of file patching output, then <ENTER> to exit

10. Select "Install Software", then "Choose Setup Executable"
11. Select Planescape Torment.app/drive_c/GOG Games/Planescape Torment/Setup-GhostDog's-PST-UI.exe

a. N: No readme
b. I: Install
c. 3: 80% bigger fonts for English
d. Lots of file patching output, then <ENTER> to exit

12. Select "Install Software", then "Choose Setup Executable"
13. Select Planescape Torment.app/drive_c/GOG Games/Planescape Torment/Setup-PST-Fix.exe

a. 0: English
b. N: No readme
c. I: Install
d. I: Install Dialogue Spelling/Grammar Corrections
e. I: Install Subtitled Cutscenes
f. Lots of file patching output, then <ENTER> to exit

14. Select "Install Software", then "Choose Setup Executable"
15. Select Planescape Torment.app/drive_c/GOG Games/Planescape Torment/Setup-PST-UB.exe

a. 0: English
b. N: No readme
c. I: Install Recommended Unfinished Business Components
d. I: Install Expanded Deionarra's Truth Mod
e. N: Not Install Restored Cheat Items
f. Lots of file patching output, then <ENTER> to exit

16. Select "Install Software", then "Choose Setup Executable"
17. Select Planescape Torment.app/drive_c/GOG Games/Planescape Torment/Setup-PST-Tweak.exe

a. 0: English
b. N: No readme
c. 2: Interparty Banter Every 6 game hours (30 minutes)
d. I: Install Dustman Robes Area Restriction Removal
e. I: Install BG2-Style THAC0 Display
f. I: Install Stackable Rings, Charms, Bracelets, Scrolls
g. I: Install Explore City Areas
h. N: Not Install Scale of Souls
i. I: Install Save Nordom! Tweak
j. N: Not Install Disabled Stat Minimums
k. I: Install Maximized HP Per Level for TNO and Party
l. I: Install Maximized Friends Spell
m. N: Not Install No Battle Music
n. N: Not Install Use Floating Text Font Globally
o. N: Not Install Identify All Items
p. N: Not Install Early Glabrezus Tweak
q. N: Not Install Power Action Leprechaun Annah
r. N: Not Install Easter Egg Morte
s. 1: Install F5 QuickSave, F9 QuickLoad
t. N: Not Install Rest Anywhere
u. N: Not Install Tome Of Cheats
v. Lots of file patching output, then <ENTER> to exit

18. Select "Set Screen Options"

a. Override Wine control of Screen Settings? => Override
b. Virtual Desktop at => "1440x900"
c. Done

Hi zackymacky,

I am trying to follow the steps in your post and i am stuck on "Choose Setup Executable". It opens up standart dialog with all programs greyed out so i am unable to get into Planescape Torment.app. How did you solve that problem?

I am using OSX 10.12.3, Wineskin 2.6.1.

Thanks in advance.

Thank you for the guide, really timely as I was just about to go through the process.

Only thing I'd add is a mention of fullscreen in the screen options for those that don't want it windowed. I was able to trick it.

Right-click > Quick Look, then click on the X or use spacebar to close that. Now it's not greyed out so you can double-click or select "Choose."

That will launch Wine Explorer and you can navigate to the executables. It's easier too because then you can run them one at a time from there.

Cool hack, thanks.

It finally works! This should be the install guide for *all* Mac users (not just those experiencing this one problem).

Thanks Zackymacky!

Fantastic! Thanks to everyone!