Now I tried this on basic long skinny cross country skis and it is fun and fast they are absolutley worthless for climbing and down hill for me involves trying to go as fast as I can so I can fall and slide well down the rest of the hill

I am 5'7" 238 pounds and carry a backpack with me with gear so the cross country ski's are not fun and or stable for me, especially with my bad knee.
I ordered a pair of rossingol BC125s G3 Targa bindings and Scarpa T4 boots. Obviously wont glide as well as my cross country boot set up but should be more stable I hope?
Can you folks make some suggestions for peripheral gear? Waxless ski glide wax? spare parts for bindings?
Any basic do's and dont's?
How does my set up look for a big guy? (well used to be 280 pounds now 238 )