On my Sandman I have 235/60 14's on GTS wheels on the front and 245/60 14's on the rear on widened GTS wheels. When I bought it it had the same front and rear but I needed something to fill the rear guards out a bit and had the 8" wheels, so I threw a pair of BFG T/A's on.

The 235's on the front are fine and don't feel heavy on the steering, in fact they are lighter than the 225's on 7" wheels on the front of my other van.

235 sounds wide for a 6" rim but the bead width isn't that much wider than 6", they just have a bit of a bag on them.