Bolt thrust isn't purely a function of square inches and psi. The type and condition of the chamber and any source of lubrication between it and the case is a big factor.
Absolutely true, so there is some room to argue. But rather than get angles and cosines of the chamber walls, derive the coefficient of friction, and test the brass for malleability, it is easier to approximate the bolt thrust by chamber pressure X case head area. It may not be precise, but then neither are a lot of other values we throw around. But this I can say fairly confidently: higher chamber pressure will translate into higher bolt thrust.
Anyway, since your 95 is designed for rimmed cartridges and you want an impactful chambering, I would take a serious look at 450 Marlin, 444, 405, 348, 30-40 Krag, in that order. 45-70 does not leave a lot of room at the edge of the bolt for stuff like extractors, bolt face relief, etc.