I did a conversion like this on a quicke 500 I have. The orginal standard size servo was mounted at 45 degrees to the wing, I replaced it with two mini servos (got an additional 10 in/oz total torque also) It worked out very well. I only ran into one problem, if the throttle was in the stop position, the extra rod protruding from the servo conectin was locking out the left aileron. I found this on a dead stick and as I started to make my final turn, it just wouldn't turn. When the engine flamed out, I cut the throttle and was having a nice aproach until the speed dropped enough that I needed both ailerons to bank it into a turn. I was so taken back I forgot about the rudder.

The quicke 500 has a very tight radio setup and the two small servos helped quite a bit in this case. I'm rebuilding the wing now after another crash and this time I'm going to put the mini's outboard a bit. That will give me additional clearance inside.

Don