Congratulations on getting an entry, lighten the alpine up or get a five with 150/60 up front,1×10 with a 32 should be ok, less chance of dropping the chain,good tyres aswell it’s very rocky in that area so puncture risk is high
As for riding with Guy,I’ve been out riding with him a few times sound bloke mad as a hatter and fit but he ain’t no downhiller I wouldn’t have thought he’ll be challenging the top positions