I think I would not be the right one to answer the question since I do not have expertise in preferred stock. Still I think the stocks can be redeemable at 25 dollars per share on the 15th of June 2026.
I would say none. Trade as per our interest and at the right places so it can be 1 or 2 or even 50. But it should be right and should give you good returns.
As a beginner don’t go beyond 100:1. And for that use a broker that is flexible like turnkey forex where you have different leverage options to use from. Also, start with only micro lots.