That 1000 mAh pack should do fine. The 20C rating implies that it can comfortably source 20A. The real limit on current delivery in this setup is those little orange JST connectors. Fortunately, for the fraction of a second the power needs to be delivered they can take it. To use a bigger battery you'd wind up needing an adapter to go from whatever connector it had on it to the little orange JST. Doable, but fiddly.
Be sure you have an appropriate charger as well. It looks like that battery has the most common balance plug on it, so there are lots of inexpensive chargers that would be suitable.
I've loaned my PSII controller with the LiPoly in it to TARC teams and had them fly all day and only need to put a low single-digit percentage of the total charge back into the battery afterward. Likewise if I go out for a day of flying on my own. (I use an FMADirect [now RevoLectrix] Cellpro 4s charger, which gives me this info).