This is the real important part. If you are off hand or on a bench.
I think maybe 24x to mid thirties max for your purposes on a bench. I do my load development at 200 yards with a sightron fixed 36 and it is hard on my eyes while I try and look at the windflags (not through the scope) and then look through scope and stay on target waiting for the right wind conditions. Not sure how small your targets are, but my 36x has a 1/8 moa dot and I use a 1" circle sticker at 200 yards.
But if I were setting up a rifle for what you are doing, I would check out one of those Arken light hunter scopes. Really nice glass for the price, Nicer than my Sightron S2 36x. Also has the magnification range that should do you very well out to 200. It's also only 23.7 ounces. I have used this one and I like it alot. It's waiting to go on my 6.5x47L build once I get it back from pierce engineering.
EPL-4 6-24X50 FFP
The EP-L (EP Light) is our Light Weight Hunter version of the EP (Extreme Precision) series. It is built on a streamline 30mm main tube to reduce overall weight with our toolless, easy to operate capped windage turret that lets you set and forget.
www.arkenopticsusa.com