"what pisses me off to this day is that twat still owes me 60 grand"
OP this is your problem. You are holding on to this idea as though it's a fact. It's not a fact and it never was.
You did the work for him on the verbal understanding he would pay, he conned you but you never had a legally binding agreement and he was never going to.
The 60 grand appears to be a sum you have personally estimated not one you agreed upon
He never owed you 60 grand
He does not currently owe you 60 grand
The fact that you have a criminal conviction for defrauding him of 2k and he has no criminal conviction for failing to pay you 60 should tell you this
The problem that you have with this is that you're refusing to let go of the idea that you were morally in the right, and maybe you were but you lost that high ground when you bounced the cheque to get a princely 3% of what you perceived he owed you and called it a victory.
I can't get my head around why you still think this, and are still holding on to it understandable at the time maybe, blame it on your youth but not so much now.