I want 18x10s for my Skylark. What’s the common 18x10 offset for a 1968 Chevelle

[STREETFIGHTER50]

I figure my car has about the same clearance as the same year Chevelle. I’d like to buy a different staggered set. 18x10s with a 295 tire would look much nicer on the back of my Skylark. I currently have US MAGS wheels in 18x8 (245/45) fronts and 18x9 (275/40) rears with more room to spare. I have 1-inch clearance on both sides, inners and outers. The fenders were opened up a bit during restoration.

Few Q’s:

-What’s the common offset/backspace for 10” wheels on a 68/69 Chevelle?
-The Weld S77s are looking really nice IMO. Where’s the cheapest place to order Welds?
-I like the “stepped lip” look better. Any other wheels y’all recommend recommend priced about the same?

Here’s some clearance pics.