What type of vehicle are we talking about first of all , are you wanting a firmer shift ?
As for the pin most of the time you can get away with using the same pin and some times you have to grind the tip just a little to achieve proper band clearance.
Putting in the vette servo will not change band clearance but changing to an after market 4th servo cover,piston can change band clearance.
1/16 - 1/8 '' is ideal band clearance in most 700r4's , here is how you can check it >>>
Before you remove the original servo cover either mount the trans in a fixture or simply place it against the wall so you can push on the servo cover to see how far it moves inward away from retaining clip because that is your band clearance > that is where you don't want more than 1/8 " , no less than 1/16 " clearance .
After you replace the servo with the ones you choose be sure to check the clearance again , adjust if necessary then .