Your load with Power Pistol is on the anemic side by a tad.
The 5.0 gr HP38 is good an should function in most pistols.
Personally, I have found Power Pistol to be more effective if start loads are 6.4gr up to 6.8 gr. These load levels are within the min/max parameters are given in the Lyman Cast Bullet Handbook 4th edition.
The velocities, in my experience, have been from approximately 800-860 fps.....with Power Pistol.
After I started using VV N340 a few years ago, I hardly use anything else. Nothing wrong at all with the powders that you stated, just I personally like the N340 better.
Regardless, you have to load up enough to function your pistol or they are for naught.