Yeah, I generally do this, and not just for a team, since I don't use the same team all the way through the game. I work out of a pool of pokemon and constantly rearrange. By late in the game, I might have 30 or 40 pokemon in that pool, and that many more that are on the second string and maybe going to get bumped up.
Before I do anything notable - generally either challenging a gym (or the E4) or going through a cave or such - I'll level everything I'm considering taking with me until they're all more or less the same level. It doesn't have to be exact, but it has to be close, because what I want to find out is which competing ones are better in which ways - who's faster or bulkier or stronger or whatever - and the only reasonable way to compare them is if they're at pretty much the same level. Plus, investing that much time into them gives me a much better idea of how they each perform.
For level, I pretty much just go along with the game. GF has gotten pretty good about consistent level curves, and since I rearrange my team to suit whatever I'm doing, I usually have type advantage, so I generally just level everyone important up to whatever the current highest level among them is, which is usually about the same level as what I'm currently fighting and a few levels lower than what's coming up, which is exactly where I want it. That gives me the challenge I want.