Wheel fitment

[shenk10]

I am in the process of fixing up my '82 c10 and am looking at wheels now. I want Boss Motorsports 338s. I would really like to run 20s but am a little worried because they only come as 20x10s. The specs are 6.225" backspacing and +20 mm offset. Is anyone running anything like this or even these?


Another option would be either 18x9.5 or 18x8.
18x8- 4.517" backspacing, +2 mm offset
18x9.5- 5.031" backspacing, -4 mm offset

I am planning on doing about a 4" drop all around so I'm wondering how any of these would fit or recommendations. Thanks

Jordan