Master Airscrew three blades are nice, reasonably priced prop. I have experimented with them quite a bit. The pitch on MA props is measured differently by the factory, so they tend to measure 1" under what they say on them when measured on a Prather pitch gauge. Go to their website and see what they have available in three blades for glow engine use. I don't have a current list in front of me, but their older packaging didn't list much in the 11" range other than a 11-7 and 11-8. They are easy to repitch, and hold the setting once you are satisfied with it. I have used their 10-5 quite a bit and it may be what you want to start with. This prop was added to their listing years ago due t the efforts of some one here on Stunthanger, who contacted the company asking for something with less pitch. His name escapes me right now, but he announced it here on the open forum and took orders. Windsor Propeller has kept it in their line up ever since and it is available in a left hand prop now also. I think their sizing jumps up to 10-7 after that but it should measure 10-6 on a pitch gauge and can be repitched to a 10-5 if necessary. Their more recent props of all kinds seem to work better that they did years ago and have a better airfoil. Just sand off the flashing left over from molding and check balance. I would take a 10-5 right out of the package, clean up the flashing, check balance and try it on your Vector and go from there.
Type at you later,
Dan McEntee