Typically, drywall returns (new construction) but right into a receiver pocket on a new construction window or to the frame. There is no classic reveal in that case except the additional width of the frame beyond the 1/2 sheetrock. If you are doing a stool, most will come out beyond the wall (obviously) and have small returns on the side and be supported by the apron trim on the bottom.

On your second picture with the trim running up each side is there additional width between the Sheetrock and trim? Sorry, I misunderstood what you meant by "except the additional width of the frame beyond the 1/2 Sheetrock".

Also, where did you get your materials from?

Thank you very much for your response!

That is just a picture from Google. That isn't additional trim on the sides as much as it probably is a bevel on the frame. You can trim out between the drywall and the window with a stop type material if you like.

Want to leave enough room for the lift handle/rail at the sill Areare is a double hung.

So there is no reveal at all with that style window trim, correct? I think I am still not able to explain correctly what I mean. Regarding the trim pieces that are on each side of the stool (that run vertically along the window), do you need to leave a 1/8 or 1/16 reveal on the drywall or mount flush?

Thanks again.

Flush.

Thank you!