Thank you very much for providing this data!
From that Hodgdon data that look very close to their max load (again this isn't data for CP) of 1151 ft/s.
Would backing off ~10% to 3.8 grains from your load be your suggested starting point? Or do you think that 3.9 grains might be a safe enough starting point?
It's always good to work up the load with your gun.
Plated data is somewhere between lead and jacketed. And with no data on Hodgdons website specifically for platted bullets, it is hard to say what the actual max load is. My OAL is also longer than the lead or jacketed data that is listed which provides some safety.