Return URL for Pro Sites / Paypal settings

Hi, I'm having issues with the PayPal settings on Pro Sites and submitted a ticket yesterday blah joy. Then today I went into paypal and realized I need a 'Return URL'. E.g, in my old install S2 Member gave me this:

Does pro sites need this? If so,where is it for Pro Sites? There is also an option to turn this off in Paypal. Should I turn this off?

Also, the old S2 member required a PDT or Payment Data Transfer token from Paypal....paypal has it but there is no place to enter this in Pro Sites. Is it needed? Thanks.