Lafool

Just wondering if I can get a little info on 19 inch wheels and the correct offset? I currently am riding 19x8.5 (f) and 19x10 (r) Carlsson evolutions on my E420 (210) with spacers front and rear. Looking to re-place them with a staggered set-up just wanted to know what offset is proper without using spacers or are they needed in all applications?? looked at a few set-ups but none were 19x10's only 19x9.5 does this make a big difference?

The wheels I have now have an et 40? with 5 or 8 mm spacer (f) not sure what the rear are.

Luke or somebady please help...these carlssons weigh a ton and I would like to replace soon. thanx