I am of the firm belief that more putters is better. Preferably all the exactly the same.
Less time walking and more time putting.
When you get in a groove and are hitting several in a row and reinforcing your muscle memory you don't have to stop and go collect putters.
When you realize a glitch in a putt you can keep putting to correct it.
With 10 putters you should be able to make 100 putts in @ 15-16 min. Even faster with 20 putters. It is hard for me to carry/stack more then 20 putters back to the station.
Practice makes putts, Don't practice without PropPutt