Your 1" OD slug tubing will have to be reduced a bit to fit inside your 1.125" tubing. The stock frame tubing is 0.065" wall so that's fine. These are the sizes I am currently using.

If you wanted, you could go with 1.125" OD, 0.125" wall which gives you 0.875 ID so you could use 7/8" tubing for the slugs so you'd save having to reduce the slugs OD as much.

cheers
myst1c

"Know the smallest things and the biggest things, the shallowest things and the deepest things."
- Miyamoto Musashi