Tire size bagged 64 20X8 wheels???

[fast&low]

Hello guys this question is for a buddy of mine not for me.
My buddy just picked up a set of 20x8 Dodge steel wheels re-drilled 5 on 5 for his 64 C10 fleet side he plans on bagging it in the near future so my question is what would be a good tires size for that set up? He won't be laying frame just a mild bag kit.
Don't know if I asked all the right questions or gave all the info needed?
So if there's anyone out there running the same set up any and all information would be greatly appreciated.
Thank you for looking & your time

[LVPhotos]

Depends on overall height of tire he wants. For instance I run a 295 / 45 / 18 rear at 28.5 ". A 255/40 =28, 255/45=29, 255/50 =30" for the most part 11 inches wide.

[fast&low]

Thank you LVPhotos & the thing is he doesn't have preference he just doesn't know what would work best for a 64 on bags with 20x8 wheels he has only owned this truck for a year now & is just now learning new things about what you can do & can't do with this body style.
But I'll definitely tell him to go by your tire height except for 20" wheels.
Thank you for your time.