As to jug-choking - I once built a .44 cal. muzzleloading smoothbore that I lapped in a .004" jug-choke. It shot nicely even patterns with 1/2oz of 7 1/2's (10 straight on trap) and also would head-shoot bunnies at out to 50yards with patched round balls.

I would be inclined to try patched and undersized balls to start with. They will reduce pressure over full sized balls or slugs and will also eliminate any leading.

It is a place to start- perhaps overly cautious for the Paradox 12, maybe not.

Track of the Wolf . com - (all one work) sells balls of these sizes in packets of 25 balls and would be the least expensive & easiest place to start.

In the 10 bore (actually 11 bore), I'd be thinking of a .735" ball and .015" ticking or denim patch for a very tight bit to the bore. I would lube the patch with something like neetsfoot oil, or a black powder bullet lube softened with Vaseline or Neetsfoot Oil. Do not use Neetsfoot Oil compound, only pure Neestfoot Oil.

In the 12, the same idea with a .690" ball and same patch would also work.

The balls are quite light compared to paradox bullets, of course.