Really what you want to do is figure out how many amps you draw as a maximum and go from there. That way you won't be over working the pack when you go to high throttle. I'm betting you'll want a 3s4p pack and then prop to suit, but maybe a 4s4p pack would be better. Ask the LiPo dealer you choose to help you out on that.

Esprit carries the Thunder Power line of LiPos. That's the brand that Jason Shulman is using in his pattern planes.

Here is a link to Esprit. http://espritmodel.com/

You'll need a charger capable of handling LiPos. Only a few of them out there are good at it.

Wiz