Just have to understand and comprehend that the center post is the positive, and the outer threaded post is the negative, and you don`t want those to get anywhere near close enough to cause a dead short on the top of the battery. If you know that, choosing a tank that will work properly should be reasonable decision. If the positive post is was too short for comfort (<1mm), if it it has one of those fancy new collapsing posts, or is a post that will collapse when pressure is applied (Kanger pro tank, ect) it is immediately disqualified for use on the SMPL.
My favorite tank on the SMPL is a Orchid. Most have a nicely protruding center post that is solid. But it is up to user to understand this and safety check it themselves! I did get one orchid that had a bad=short insulator in it that allowed the center post to get pushed up, which I fixed with a new delrin insulator.
PS, on tanks that have a screw out center pin. These can get screwed back in with repeated pushing on the button. What you want to do is place a couple of good o-ring (or better yet a delrin washer) on the this to make sure it wont get screwed back in far enough to become an issue. Obviously the operator is responsible for all user error and safety issues that can or will become relevant when using this direct connection system.