The Lyman should be good to 50 grains of 2fg with a PRB,
The CVA tower pistol is a different animal and a max of 25 3fg and a prb is about it.
Whether you you a heavier or lighter patch and a 530 or 535 ball matters less.
Be very careful of how tight your patch ball combo is. Some shooters really have to bruise their palms to start the patch ball combo down the muzzle of their rifles. To do that with a pistol requires the butt of the grip to be on something hard like a bench. A sure way to crack a pistol grip. A fair number of TC patriot pistol stocks were broken by shooters trying to pound tight PRBs into the muzzle. I have heard of a few Lymans being cracked the same way.
Since you have two, I suggest a loading stand. They can be as simple or complicated as you want, but the idea is to let the stand hold the pistol upright for loading. There are plans on line or finished stands available on flea-bay and elsewhere.
Scroll down to page 13 for the page about the Tower pistol. Yours is the earlier model made before about 1980. The lock is slightly different in 1982. The other difference is that until about 1980, the tower was made at the Jukar armory in Spain. About 1982, the same gun was made at the Ardessa Armory in Spain. There was also a change in the trigger and trigger guard as I recall.