I have a Super Tiger .61 in my Freestyle with an APC 12.25x3.75 prop turning 14,000 rpm.Vertical performence is unbelievable,the thing never even slows down. I can hover at half throttle and when you slam it to it,it accellerates vertically like it's tail is on fire! I know the stock gear is flimsy,but I would keep it. I tried a heavier gear on mine.Slowed the plane down and made hovering tougher.There is something about that lightweight gear tucked way up in the body like that,that seems to helps it's "vertical balance",if there is such a thing. I didn't seal any of my hinge lines and have not seen a hint of flutter,even in a power dive.(right before a mind blowing Blender) however,it is very good advice to seal them to make SURE you don't have a problem.I used standard Futaba S3003 servos all around.I think a stronger servo on the rudder would be beneficial for pulling out of knife edge loops,but the standards seem just fine.My plane also balalnced with no added weight.Hope you enjoy yours like I have mine.It is truly an underrated airplane!.
Rusty