I'm missing what your purpose is for your rifle TP. "Lightweight AR" to me means you intend to move around a bit with it, whether busting brush or dynamic shooting, and are looking for the full range of shooting spectrum.
With the exception of my MK12 Mod 1 (near spec build including 2.5-8x32 Leupold scope), all my small frame ARs have a 1-?x scope on them or an Aimpoint. I like lightweight and fast up close for them as a significant option, and the distant shooting I find 6x or 8x to be more than enough on the targets I use. Anything beyond 600yds <1/2 IPSC sized targets, I use larger calibers that defeat the wind better. Anything paper-punching or precision (including small varmint hunting), I'm using the .260/.308 bolt guns or rimfire. I'm finishing up a 6.5CM semi to plug the gap, but that's still a work in progress.
I've tried 3-9x, fixed 10x, and even ran a 3-12x50 PMII on my 5.56 ARs. None of them did what I was really looking for, made the rifle bulkier, slower, and more limited.
Not trying to say you need to change your optics decisions, simply giving food for thought from my own experiences. The "what/where/how" would definitely help in providing advice to you.