I'm getting 24x12 Deerview windows for my blind build and would appreciate your input on the best lower window ledge height. I don't want it just for me, I could figure that out, but a good average height. Thanks.

This what I did. Had wife set in chair, had her hold a rifle on set of shooting sticks, measured to the rest of forearm. The I did the same. She is 5-6 and I'm 6-0. With a proper office chair where the height can be adjusted, this worked for me.
If you are going to have a ledge in front of the window you could use a bean bag to adjust the height for the right position. Just don't get the upper part of the window to low so that you have to scrunch down to see out.

Harley nailed it, I like to us adjustable chair also because I have multiple feed pens at different angles of impact. I like to be able to adjust quickly and with the pull of a lever

Every one I've built I've put them at 36". Seems to be a good height, works well with the adjustable chair the other guys are talking about.

Thanks. I really hadn't put any thought into an adjustable chair. I appreciate your experience and knowledge.

Also take into to consideration the elevation of the blind. If you are shooting downhill, level or uphill a bit. That will effect the height of your window a bit also. I use an adjustable chair in all my blinds and window bottom is 42" for me.

What stxranchman said about up, down and level. I have one that is 36" and one that is 42" But, even with adjustable chairs, my grandson has difficulty shooting out of the 42" and I have difficulty shooting out of the 36" I'm thinking 38-40" might be a good compromise for most folks.

My box blind has high windows, so I use a drafting stool to compensate. I like that I can stand and stretch a d still see out the windows. My two man blind has windows at 38" so we use regular office chairs there.

X 2 on 36". All depends on the person and the chair height.

Aside from me, my son will be shooting from it the most. He's 10 and I know I'll need to allow for growth but need to consider his size now too. Also, I'm going to elevate it six feet. I don't need a tall tower and don't like the sway in the wind I've experienced in taller blinds. I may build a small frame and see which height functions the best for him. I can improvise easier and I don't want him to be the one to adjust. I really do appreciate the input.

40"

Listen to this man! He builds a mean blind.

Built six 4x6 blinds. Window cut on all at 40" with a shelf 1" below window. Use small sand bags to anchor in. Have Executive high back chairs with rollers which have hight adjustable pedal. Floor cover is indoor/outdoor carpet.

I do 40" with adjustable chairs.
We have a 20ft tower blind that has 44" high windows, that is way too high for shooting at a down angle. We had to put a platform under the chairs just to see out.
We had some ranch helpers build a blind (we told them to just make them like the others), well... they put the window openings at 5ft high. They thought standing up to shoot was better. Although that would work, all you could see while sitting down was the blind wall. Helpers weren't too bright.