I could not pass up a deal on a new 50 mm carbon rear (75% off retail). Now I just need to find a front. Is it worth it to find a match, or does a different company and rim depth matter much?
what was the deal? you can’t just tease us with a 75% off retail 50mm wheel and not say what/where it is…
doesn’t need to match, get the best front wheel you can find.
The only thing that should match is whether it is a tubi or clincher that’s the only thing that should match.
Not necessarily. For ease of carry spares fair enough tub/tub or clincher/clincher, but the OP might want to match carbon tub with alu tub or carbon tub with carbon clincher.
There is no rule that says anything has to match. I have run alu rimmed tub disc (Mavic) with carbon tub front (Planet X), carbon tub disc (Xtreme) with alu rim clincher front (Hed H3). I can’t even make a pair branded up with the same company logo.
To the OP: You could always buy some wheeltags and sticker any wheels up to match. I’d suggest getting the best front wheel you can afford. You can always stick the rear 50mm on the road bike when you buy a disc 
it is probably wise that the tires match, so that you don’t have wildly different levels of grip in a fast turn =)
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different company doesn’t matter. my race bike has Zed and Hipp… wait a minute… and I’m sure it’s not slowing me down.
different depth might - don’t get a deeper front than rear.
it’s probably a good idea to have both clincher or both tubular, unless you either don’t care about weight, or about finishing after a flat.