The 505t and 503C go very well together. When my 505t is to much I normally go to the 503C. My 505T is about 6 or 7 boards stronger then my 503C. I am not sure if the 503C will give you the big back end you are looking for. Its more of a smooth arc reaction. You would be able to go from the 505T to the 503C and play a smiliar line, even might be able to play a little straighter with it. Hopes this helps.

You can dill both the same. The 505T should start up a little sooner. I have my 505T drilled with the pin just under my ring finger it was not drilled dual angle. It is really good in oil starts up a earlier then the 503C and still pretty good back end on it. The 503C was trilled dual angle it was drilled 50 X 00 X50 sorry don't remember the middle number but could find out in a week or so when i go back to the shop I got it from. With that dual angle sum its the middle of the road of my range. So it gives me a nice smooth roll all the way down the lane. Its very consistent off the spot and predictable. My states are about 18.5 mph off the hand revs 380 ish. 74 degree and 12 for axis and tilt.