"a collection of relevant numbers—SSN and DL#, which tend to be stable over a long time" -- where I live, you get a new DL# every time you renew your license, which includes every time you move. I'm not sure that exactly qualifies as a 'stable' number.
"at the discretion of [HP/S], I will pay as much as requested, to [HP/S] to further his/her work in the Craft" -- ummm, we already have HPSes who are having people clean their house for free before circles. Yes, really. So I'm not at all sure that giving them a meal ticket for the low low price of throwing a false accusation is necessarily an improvement.
Thirdly -- who's going to enforce this contract, given that little prohibition against putting Craft on trial in the courts of the land?
I'm not sure that anything is an improvement over the original, but YMMV -- :Dana