My experience has been with both the Javelin and the Oxalys models using a YS .63S. With YS 20/20 fuel the .63 liked the APC 13x6 the best. The APC 12x8 just didn't have any grunt. As of late I've been burning Magnum 30% Heli fuel and using a APC 13x7. The setup has run flawlessly for me. I'm turning 11200 on the ground at WOT.

Clay