This hobby is so subjective and at the same time it's also so hard to actually test switches in person. It can be very frustrating. Greens would ruin me I think. I almost got them on my first board, based on description alone, but I'm glad I went with blues.
I'm a little concerned about reds being too light. I want to try gateron yellows/blacks but can't figure our a way to test them without just buying a board.
That is exactly correct - this is all very subjective.
One person's ideal switch might be a nightmare for someone else.
Massdrop sometimes has drops for switch testers that include some Gateron and even Kailh switches.
But pressing a single switch will not give you a real feeling for typing on a keyboard with that switch in it.
Depending on how soon you want to buy, can you get along to
KeyCon 2016? Date TBD apparently, but if you have no urgency then attend, if you can - there are usually dozens and dozens of keyboards with all sorts of switches and modifications that you can try.