As per a comment from Jetwash in DTG Forums, he no longer uses NVIDIA image scaling and has a screen percentage of 90%.

I tried these settings and they are good with a near constant 60 FPS on NY Trenton.

https://forums.dovetailgames.com/threads/enhancement-tsw4-specific-lighting-graphic-enhancement-v3-3.74685/page-4#post-753389