newer wheels on one ton - help

[bucket]

i have a set of newer one piece dodge budd wheels for my 70 dually. i think i need to change the studs form 1/2 to 9/16. the hub opening in the wheels is larger than the hub itself, meaning the hub does not support the wheel, only the lugs. normally, don't the wheels fit snug around the hub to help with support? should this be a concern?

also, when was the last year for drums on the front of a one ton? was it 70 or later? the front studs i'm finding are listed for one ton disc brake applications. will these same ones work on the drums?