If the Oktavas are at the top of your budget, that's what I would get. I don't think you're going to do better than that until you spend more. I would definitely pick SDC over ribbon, as well. The Oktavas don't have as much "air" as I like in a mic, but this doesn't manifest itself on acoustic usually.
shit i forgot to mention i modded my mk012s its just been a while so i forgot. just simple recommended parts upgrades like higher quality caps to make them less brittle i use them as my overheads on drums and i love them. i think i spent 400 on the pair and then 100 for all the parts in a kit but i didnt end up using them all. once again good luck mic hunting and also buy a new acoustic if yours sucks. all the mics in the world wont make up for what the guitar doesnt have.