Just stuff your pockets with some money and get right out there and buy a big bunch of props and start having fun doing some testing!! Prop/engine/plane combo is a pilot thing and you need to do the testing so you can find the combo that makes you, the pilot happy.
For myself I like a slower plane with as much thrust as I can get, I would be looking at the 12X4 or maybe even some of the odd pitched 3-D props for something even a bit lower in pitch.
One of the nice things about where I fly is the people. If we know someone is doing some prop testing we will take out a bunch of props and we end up with a big pile of them for the guy to test. Saves a bunch of money.
If John says an 11X7 you better have one in your box. I'm sure he has tried them all by now!!!