Do you think a G80/85 with ibis/dual is would result in more stable shots than a g7 with a gimbal?
A good gimbal will be more stable than IBIS - but the G85's IBIS is pretty darned stable, as in this example (all shots handheld except for the night shot at the end):
Which do you think would be the more affordable purchase?
Here's how your numbers play out:
Panasonic G7 with gimbal
Panasonic G7 body used - $450
Total Price: $949
Panasonic G85 with IBIS
Total Price: $897.99
In my view, the G85 will cost you less - and eliminate the hassle of keeping a gimbal powered and balanced.
Hope this is helpful and good luck!