You can see from the pic that the (-) offsets will stick out further and the (+) offsets will move toward the suspension.
Stock offset is (+) 25 mm with a 5 5/8" backing, I believe.
a (-) 6 mm offset would push the wheel in towards the suspension a bit more.
Here's a good calculator:
http://www.1010tires.com/WheelOffsetCalculator.asp
Seems to me, the 10" wide wheel is going to cause you more grief than the offsets you mention. The 10" wheel is going to cause both the inside and the outside to be 1" further away from the hub, and possibly rubbing both the wheellwell on full lock and/or the suspension components.
Even with a lift, some have had rubbing with 10" wheels.