Should be more than enough, my go to was always SLX and never had any issues, even in France / alpine descents. The 4 pot xts will be fine for what you want
How much you weigh compared to him is the real question
I'm probably about 100lbs heavier and at least four times as slow
Fixed that for you. You shouldn't tell lies Darrel
I feel like you kinda get used to whatever feel your brakes have to some extent. If your brakes are grabby you get better at feathering them. If they have a lot of modulation you pull harder etc.
Shimano and SRAM brakes are both very usable imo. I've just always been a Shimano guy and stuck with that.
I thought my Avids were fine , tried guides and thought they were finer , tried codes ,finer still , never tried any Shimano stuff , I am sure they are fine