This will result in having Tandy sound but not forcing Tandy graphics.
Just curious... what is the gain of not forcing Tandy graphics? For AGI games, it's just trading one 16-color standard for another. I cannot find any visible difference in either configuration, and I find the "machine=tandy" approach to be less work, requiring modification of one file instead of two.
Again, just wondering what the gain is. Maybe I'm overlooking something.
(sorry for the late reply!)
Purely personal preference. Tandy graphics look slightly "different" to my eyes (mainly the text), and I prefer EGA due to nostalgia. Also, since first emulating these games in DoxBox, I've always just used "-t" so that's what I'm used to as an adult, too.
In terms of "less work", I usually play these games with my own pre-made shortcuts or D-Fend Reloaded (front end), so changing files isn't a concern of mine. I'm very happy that we have all these *choices*, even with the official GOG releases now, though!
Amusingly, when I first played these games as a kid, I only had a CGA monitor and played them in black and white (looked better than 4 colours!), so my oldest memories of the early Sierra AGI games are always of looking like that. Obviously, it's nicer to have colour now, but the Manhunter series (one of my favourites) does have a rather nice noir feel in B&W, compared to the rather garish gore colours of EGA. :)
PC speaker is also how I experienced these first, but I love the 3-voice Tandy music too much to sacrifice that! With the later games, I often lend to go with AdLib even when better is available because that just sounds "right" to me, again purely due to how I first experienced these games as a kid and teenager.