Sounds like a good build you have in mind there.
I run Magura Durin Marathon 120mm on mine. The X0 kit should make a very light build possible. With X9 + XT on mine it was coming in at about 24.5 lbs (a little more now that it's gone tubeless). IIRC the frame weight is something like 5.2 lbs for the large.
The 2.25" tyres steady things up significantly, imo, and make doing (Welsh) trails centres very doable – just need to pick a line more than just my usual thud and blunder on the VT so, as you say, some finesse needed. And it does climb beautifully, leaving you less knackered and so more able to concentrate on descents.
I have heard great things about the EX. The SL's simplicity is a real plus point, it's required minimal maintenance. When I bought it, it was that and the mud clearance that edged it over the Anthem or the Top Fuel. More travel now on the Anthem would've made my decision even harder!