I recently purchase a 12 lb. rogue assassin and am looking for a couple of other motiv balls to fill in my arsenal. I am forced to throw lighter equipment because of health issues. I was looking at the Supra or the Venom Shock as my main choices. I will be using the Assassin as my benchmark on a medium-heavy THS. I am looking for something to throw when the lanes break down or for practice when the lanes are not freshly oiled. Anything else I should consider? I have heard great things about both balls so I am excited to add one or both to my bag. Any thoughts would be appreciated. I throw the ball extremely slow, about 10 MPH. Will this make any difference?

Can't go wrong with the Supra.

I would definitely go Supra over the Shock since you have an Assassin already.  At 12 pounds the numbers aren’t much different between the Shock and Assassin therefore it’s really just a solid cover difference which IMO isn’t much of a difference.  The Supra will be super clean and probably a good match for a person with slower ball speed.