Just an opinion for you, I am also selling private hack as same as you do, private build for every single users, encrypted script...etc etc, but the only different is I am still providing Paypal for them, because you just don't need to worry for their updated policy as the protection still not including Digital soft-copy product without and hard-copy yet.
For my experience, there is one and only one customer asking for refund though submitting "dispute" ticket to Paypal just because his computer is too shitty to run a hack.What I have done is immediately upgrade the request to Claim, upload the "No refund policy" and "successful trade chat history/product send mail" screenshot in it.
Paypal will then asking the buyer to lower his refund request money, and ask if you accept it or not, just reply not accept, Paypal will then decided in your favour.and make you win, just because selling hack is violates the PayPal Acceptable Use Policy and it is ineligible for PayPal Buyer Protection, case closed within a week.
So that is my experience for your reference, because I think Paypal will be easier and more attractive for buyer to purchase it instead of BTC, just remember accept the payment though your commercial account instead of your email to advoid personal information leak.
Look forward if you can make a smoothly work "no health bar" one though, good luck.