What offset for flush fit on s13 with staggered setup

[robojew]

So I'm looking to get a staggered setup with 18x9.5 in rear and 18.8.5 in front and was wondering what offset would be needed for a flush fitment. Would be on a s13 with the only suspension mods being megan coils.

From what I gather I should be looking for around +20 in the rear and +15 in the front. Confirm?

Also what tire sizes for a mild stretch? 235/35 in rear and 225/35 in front?

[simmode1]

Find a setup you like and copy it:

http://www.rimtuck.com/thumbna...l=S13&

17x9+12 & 18x9.5+15 with 235/40/17 & 255/35/18 is a nice mild stretch, IMO. But thats wider than whats popular in the stretched tire crowds...