Honestly for the auto mode, it might be easier to use the rotary pneumatic. Just have a piece of 80/20 sittin on that and when you get closer to the wall just have it flip out and pop the ball off.
Sure, it doesn't hook it onto the field, but it's simple and effective, which is by far the best strategy to go with.
I think KISS is so 1970's (you decide if the pun is intended), but I think KISES is (are) the future.
Keep
It
Simple &
Effective...
Seriously (be nice

). Plus, KISES
is the plural form of KISS...and we all know more is better
In any event, just do one thing well. You have many years ahead to build that ball grabber/king of the field/super fast/flying/burger flipping/Bush-impersonating robot or that flux capacitor concept you've had floating around for a while...