tire size for stock wheels? 68 C-10

[burkeens]

Any suggestions on what tire sizes will work on the original steel wheels? 215/70 R15 on them now. They look a little small, but I guess that's because they are 15s. Original spare is still underneath and looks even thinner.

Also, if I go with that same size, Bridgestone makes a tire, Turanza EL400, in that size with a whitewall. Load rating is 97T. Any thoughts on if that's robust enough? I'll carry a scoop of mulch or soil in it occasionally, but it won't be used "as a truck" all that often. If not that tire, any other suggestions for a whitewall that will work on the steelies?

Thanks!