Thanks for all the input.
On the front:
So far MarksM has run the widest setup up front with his 18x10 et25 and 285/30r18's. Looking at thread by Sayemthree http://www.m3post.com/forums/showthread.php?t=154323
, he noted his setup of 18x9et35 with 5mm spacers (et30) and 265/35/18's had 8-10mm clearance to the strut. MarksM setup would be 1mm tighter to the strut leaving approximately 7-9mm clearance, and 25mm wider on the outside. Ilia@Ind's setup came up 6mm narrower than MarksM on the outside. I'm just guessing the 285 is as wide as it will get without going to fender-rolling.
It might be possible to do a 295 with a 20mm offset and rolling the fender... this would give me a 6-8mm clearance to the strut (very tight) and an extra 11mm wider than MarksM's setup, but it'd also throw off the alignment slightly. Does this sound right?
How much extra room to the strut do you think I ought to consider if I add camber plates and go a bit more negative?
Haven't figured out the rear yet, but it's much less troublesome than the front.