Friday morning wheel question [Holy Crap! Update]

I like my Sunchaser wheels, but they are too big (15x7), and I am getting a lot of rubbing, especially with passengers in the car. So I am dropping to 14 x 6.5, in these cool Work wheels.

One of the best things about these is that they are available in a lot of sizes. But they are not available locally. The one thing I can’t figure out is the offset. Any tips on how to figure this out?

[Holy Shit! Update!]

The genuine minilite guy emailed me and has my wheels!

Russell, you dog, I thought this was not going to happen. This solves the whole problem, I get my genuine minilites, and they are about half the cost of the Equip 03s.