Yes, I had done Bikram before, on and off for the past year and a half ... (more OFF than on)
However, a friend of mine who was a master cleanser, had never done Bikram before I told him about it and decided to take it on for the entire ten days having never done a class in the past.
There really is no correlation between the two things. However, they are aiming toward the same goals, healing the body through detoxification.
I just wanted to do both because I knew it would move my cleanse along a lot more productively, and it has.
You can read all about ALL of the many benefits of doing Bikram right here: www.bikramyoga.com
As far as training in Bikram a little first, personally that is the way I would do it, but like I said, my friend had never done it before (although he is a very experienced master cleanser) and got through it just fine. So, entirely up to your intuition.
Please let me know if you have any other questions I can answer.