Looking for a set of levers for my TT build. Will go on the bullhorn bars. I now understand that not all of them have reverse springs, like this should be considered optional??? Anyway, someone got a recommendation, wish I could afford carbons...

Brake levers don't really need return springs as the return spring on the caliper will pull the levers back by the cable.
Sorry, no recommendation on levers, but I wouldn't bother with the price premium to get carbon.

just buy a pair of the basic tektro levers. They look, and work well.

And while you don't need a spring, it can help with lever feel a lot, and can make up for a less than perfect cable run. I recommend it, but it's not essential.

fuzz, the tectros have return springs? While they may not be essential, not having them would be just plain weird

people have fitted Brifters to cowhorn bars too, so there's that option.

I have a pair of the Tektro RX 4.1, and they have a return spring. It's a wimpy little thing, but it's there.