My personal advise get something in the 2-18 range
A 2-12, 2-10, 3-10, 4-14, 4-16 or 3-18
I wouldn't go over 18x for weight reasons and optic foot print as well as its not needed for 1000yds
I really like my 4-14 as an all around scope but also like the vortex pst 2-10
There is an older 3-10 vx3 in the EE that fits this build nicely but I think he is asking too much, though it has credence as an spr optic for very early mk12 clone builds.
Basically I wouldn't want no less than 10x for 1000yds. I'd even try the razor 1-10 if given the chance
I also would suggest you factor in some budget for an offset rds, the 2x can be workable for upclose but really an rds isn't terribly expensive and could easily fit your budget.
If this rifle will live in the 500-1000yd range I'd run max mag at around 20x since size and weight go out the window. And mag over 20x to me just amplifies mirage.