I set up the Ultimate SiN Patch and from what I understand, it's set up for 1920x1080 which is my monitors native resolution. However, when the game starts, it flickers like crazy, as if the frequency is off, but I see no way of adjusting it.
Have you tried the Sin Patcher from http://sin.nanoaugur.net
/? I tried Ultimate SiN patch at first but I still had problems with the game so I went to PCGamingWiki and the Sin Patcher fixed the game for me.
1. Download a Sin Patcher for either 1.11 retail or 1.12 Steam.
2. Move it to the installation folder and run it.
3. Type in your desired resolution values and click Apply resolution.
4. Start a game and select 1152x864 resolution in game's options.
(Info taken from https://pcgamingwiki.com