An exact fit would be the MK retracts, and you should be able to get them through Gator. An almost exact alternate would be the the Dave Brown Southern retracts. Both of these are good quality.

That being said, there are some smaller, lighter mechanical retracts available. The Hobbico set is a good buy, but you may want to by two sets so you have spare parts. Many of the competitive fliers were using Supras until the switch to fixed gear, but I haven't seen any trike sets of those.

For pneumatics, SpringAirs are the best, IMHO.

I'd stay away from the Goldbergs.

Hope this helps. I'm facing the same problem with my Blue Angel.

-Ron