Not too long ago I did a big investigation on the offset question
with regard to my interest in 235/75-15 tires.   A friend had Momo
15" wheels with this size BFG AT's.  His offset was ET 38.  Clearance
to both front and rear suspension was less than 1/2".  Same with
sliding door clearance

I posted photos of the van and all the clearances in the "Files"
section and to syncro.org.

I thought this offest of ET 38 to be too close to the steering arms
in front and rear trailing arms in the rear.  I agree that ET 23-28
seems ideal.  That would give another half inch of interor
clearance.  Michael Sullivan has ET23 on his double cab and is happy
but he has no sliding door.

For less offset rims that cause sliding door problems, it is easy
enough to make an extension for the sliding door rear hing.  (I think
a longer hinge is even available from some list vendors.

I agree that the ET 0-15 seems extreme.   Not sure about stress on
suspension and bearings this would cause, as well as spray mud all
over the exterior sides of the van.

Get some big mud flaps.

My 2 cents.

Warren Chapman