Dave, your good to go with that Castle 45a esc... nice reputable item you've got.

Now you need to know if your pack is going to get hot (without the aid of a meter).
Try this...
After clipping the prop down, just give it all a 1-2 minute steady 1/2 throttle static run while tied to a chair or something.
It wont have any air being rammed into the cowl like it would in flight for cooling, only the prop-wash, which by comparison isnt much.
So if your leads are long enough, keep the pack out in the open, lay it on the floor in the prop-wash area.
This will enable you to touch the pack and check its temp during the test... slightly warm at 1/2 throttle under these conditions is ok.
Even if the pack stays cool, (it should), avoid the temptation of running it harder except for very short bursts... you dont want to get the motor too hot, which is easy to do while static testing. My 2818 will get noticably warm/hot while checking amps/watts with a meter, but if I check it right after a hard flight its always nice and cool, the pack is simply warm. It's all about air flow.