50 degrees should be plenty.
I have found that the entry technique that you described is the hardest one to get right everytime. Usually the reason the plane falls out of it is because you are not using enough left aileron.
On the 42 you can use full rudder, full down elev. and a little left aileron and it should work everytime. On the 47shp, don't use any rudder. Just use a tad bit of left aileron and full down elevator.
Here is another technique for entering the manuever. This entry uses the airplanes momentum in order to force it into the manuever. I have found it to be a lot more consistent.
2:05 in this video
http://www.youtube.com/watch?v=1h17CnNIFyI