Hi
The only people that will tell you not to breed VT's are breeders that consider them mutts. There is nothing wrong with breeding them, especially if you have VT's that are a different colour from the normal reds and blues. the biggest problem with breeding VT's is seeling the babies, as obviously they are the easiest bettas to find at LFS's.
As you already have a male CT, you would be better off getting a female CT. Modaz (DPfishways) sometimes has them as does Devon Charm (the betta lady). There may even be one on ebay at present, not sure, being sold by a seller called olsen.
You have to bear in mind the age of your male though? If you bought him from an LFS, he could have been anything from 6 months to over a year at that time. They can be bred when they are older, but the fry may not be as numerous or healthy.
Other places to find bettas of varying tail types -
Me & Netty
Ebay
Aquabid (bit pricey when you add the shipping)
Obviously you are a bit away from breeding at present, but without sounding boring, make sure you have everything you need first

e.g. spawning tank, growout tank, jars, microworm cultures, brineshrimp etc etc......
Good luck