19 x 10 3 blader Menz on my Sist 1/5th scale 190. Nearly the same size and weight plane as yours. Flies it beautifully. Similar results with a Menz 21 x 10 2 blader. Both turn over 6 grand.
video here:

http://media.putfile.com/15th-scale-SisT-Focke-Wulf-190

and here:

http://media.putfile.com/15th-scale-FW190A-8-video-2

If you like the way this plane flies, these are the props that work on it--yours should be very similar. Just get all the cooling to the motor you can.