The number of commas are based on how many times you'll push the button in the time it takes before you want to cast the spell again.
Based on the 44 commas in the your lava burst sequence, that would indicate it is tuned to pressing the button about 7.33 times per second.
Personally I've tuned my /click sequence on my main to about 5 times per second.
You'll just have to practice on a target dummy and see if you feel the spells are going off when they should, and adjust as needed.