[MetalMan]

For the same power output, the XL motors should run cooler than the L motors, simply because they have more surface area (in terms of copper and the longer can). That said, you should be able to get more power out of a XL when it is operating at the same temp as a L.

Pretty much all Feigao motors are going to run hot, but the XLs shouldn't run as hot as the Ls. Simply because of that, I'd choose a XL, as the small weight gain and $10 greater cost aren't important to me.

As for you already having a L motor clamp, you can simply use longer screws and have it fit the XL motors. It won't look as good, but it's an easy way to save money.

The True RC 5s 5000mah 10C could be enough, but I wouldn't trust it. I know you don't want to go 2p, but I think a True RC 5s 8000mah 10C or 5s 6400mah 15C would be a better option.