I realize that everyone is different, but I'm not sure it matters that much if you putt with a stack of identical putters, or have ten different putters, assuming you're practicing mostly inside the circle putts. I think it's more about putting in the reps than anything, and I like to vary my practice. Sometimes I do my whole "routine" on every putt, sometimes I don't. Doing the same thing every single time just sounds boring to me. The more fun you have the more likely you are to enjoy it, reap the benefits, and continue to do it.
As Corin stated, it's two parts: Technique and Mentality, and the latter is far more important. Find a comfortable, repeatable motion and do it the same every time. As for the mental aspect, you should decide and know you're a good putter. You should not be thinking about the outcome of the putt (miss or make) when you address it. It should be a foregone conclusion that the putt is going in because you're using the same comfortable, repeatable motion every single time. Pick your target and throw it in. Too often we make putting harder than it has to be because of mental obstacles that we are creating for ourselves. Get rid of those, they don't help you.