3D "throws" (the amount that a control surface moves) can be up to usually 60 degrees in either direction from neutral (flat), you will not want this much throw to learn how to fly. However you will need enough throw to get your self out of trouble if you learn to fly with a "3D type" plane. So if you end up tossing your Slick 3D into the wind to train on I would say something like 25 degrees from neutral on all controls would work good.

I know guy's that have learned to fly on this kind of aircraft and they are very good pilot's now, so it's up to you. Just make sure to come back and let us know how your 1st flights went.