Try a Master Airscrew 6x3 prop. If that prop is turning up some good rpm, then the plane should have power to fly. If it just weighs 13 ozs there should be no problem.
How about balance, is it nose heavy? Did you do a test glide to see how well it flys with no power?
That is a neat looking plane it should do well with a .049
I have a new babe bee on my LS150 and will give a first flight report very soon!