Sill angle trim is normally ripped on site and integrated to what is site (i.e. old window) dictated.

Thanks @wi@Windows on Washington Ltd. Am I misreading some of these docs (pics attached)? They seem to suggest the frame height depends on the angle of the existing sill, which would explain why, when getting a quote, one question relates to the existing sill angle (in addition to the opening height closest to the stool)... Or maybe this is irrelevant and the frame height is independent of the angle?

Thanks, @Windows on Washington Ltd ! All makes sense. So, to simplify things, it sounds like I can just specify 7 degrees for all Marvin Elevate insert units, right? It would make things easier when ordering, and all units that are supposed to be identical in height will indeed be identical...

Sounds good. Definitely would NOT be ordering multiple sill angles for a bunch of windows that are the same.

The Elevate casement is only available with a 0 degree or flat sill and double hung only available with 8 degree. So, to use the OA's words, you can specify a 7 degree but you're not going to get it. If you are using DHs, no problem, If casements, use a piece of trim and paint the same color as the sill.

Thanks, @eastbay10. This is for Elevate double hung inserts. Just got a quote with the 6, 7, and 8 degrees across different units. Indeed, the height of the frames varied very slightly depending on the angle. But, as @Windows on Washington Ltd suggested, I will adjust the quote to a common angle, likely 7 degrees (midpoint), for simplicity.

I believe Marvin also has color matched sill trim. that snaps into the frame. Nice to have on hand in case the existing window frame is out if square or if you order the window slightly short. Part number V2034.