When it comes to full ring I wouldn't do anything to change the way you think about poker. It's just a 6max game with 3 extra seats - but keep in mind that because of this the dynamics of the game change a little bit (more multiway pots and more mass tabling nits playing for rakeback and with the blinds taking longer to reach you each orbit you develop history slower and alot of regulars at lower levels tend not to make many drastic adjustments - they just play their game).

I would recommend playing something like 10k hands of full ring to get used to the new game dynamics and post hands from your sessions in the forums and/or discuss them with people on AIM etc. Then post your stats from those 10k hands to get some feedback on how things are going so far so we can point out any spots where there is room for improvement.

As far as hours to switch from 6max to full ring, I don't know. You can make the change instantly. As far as getting used to the game/figuring out what a good number of tables is for you I'd say probably just a few sessions. There really isn't as big of a difference between full ring and 6max as many players think, but they are there. And they are subtle enough that those differences could make one game better for you than the other depending on your style.