70 Chevelle Wheels and Tires- Stressful

[Shiner]

I sound spoiled saying this but ordering custom wheels and tires is stressful.

I have ordered my Weld RT-S Wheels and I did this based on a combination of recommendation from Weld and research.

I have ordered
Front: 18x8 4.7BS and 275/40R18
Note: I now want to change this to 18x9 5.2BS and 275/40R18

Rear 18x10 6.2BS and 305/35R18

I am concerned that the wheels wont fit. I have ordered a Percys Wheelrite, however, I believe Weld is backed up right now due to a problem with their ovens on the RT-S line; So I suppose I have a window. The issue is the Percy's tool makes you bend a wire over the tires you want to use... Well I don't have the fronts yet to so something like that and mimic section width.

Do you guys think I should proceed and relax or what? Should I change the wheel size to a 18x9 in the fronts or get a smaller tire and run the 8s?

Talk some sense back into me.