Guppys can be as demanding as Bettas!
First you have to decide why you want to breed for ,pets or show.
What are you going to do with all the Guppies you end up with?
For show,you still need alot of individual tanks-,the females need to be separated so they stay virgins.
Actually,show Guppies are alot like show Bettas.
My Dad and I raised Show Guppies for awhile,when I was younger.
Not trying to burst your bubble,but any fish you decide to breed can get expensive and time consuming.
I have a 55G,community tank that has Guppies in it,I just let nature take it's course and really enjoy the color mixes I get.