Hi Jaybee,
I'm told the 30A versions will be available at the end of July, these ones are a little more than the 20A versions $15 to $20 I think.
I use 15A power supply which works fine for me. The 30A discharge does not mean you are drawing 30A form the Power Supply, you are drawing 30A from the cells.
For more information on the the charging methods it's better to check out the Pro-Trak website, however generally when charging for racing I use linear, this seems to give good punch for when you are racing. For cylcling, I use soft pulse as this seems to help with the condition of the cells better.
Anything else I can help you with, just let me know.