Inferno ST-RR Gearing Question

Dear all,
I am really really new to the brushless world.
I have a question regarding the gearing of my truggy. The diff is fitted with the 50T spur which comes in the set. I am to use the 2200kV MMM, and the truggy is mainly gonna be used for bashing around.
Which would the gearing ratio to go for bashing and a decent run time?(if I could combine all these with speed I would be going )
Thank you for your help. I am gonna post my project on the appropriate section of the forums.
Cheers