I was able to find mine at my LFS. Hard to find them paired though IME. Good thing is there are good odds that they’ll pair so you could get them from diff sources. In that size tank they’re bound to find each other.
That’s a loaded question. You are only going to get opinions, honestly. All the reviews you read are exactly that, reviews. Each person’s own experience with that particular vendor. There is no right answer, there MAY definitely be a wrong answer, but no perfect vendor. Good luck with whatever you choose.