I can't really help you in that I've not tried too many 200gr bullets with Power Pistol. I do know that a 200gr Nosler JHP (1.130", CCI Small Pistol, 1x Winchester brass) over 6.3gr Power Pistol averaged 906 fps from a 3" Kahr CM40.
I know that doesn't exactly help you out, but for what it's worth, it was very consistent and shot very well. I have some 200gr Missouri "Steeler" hardcast bullets that I plan to load between 6.0 and 6.5gr using Power Pistol.