Holy Crap!!! You don't even know how much searching I have been doing to try and find someone who will verify which offsets on these wheel sizes will clear those exact tire sizes. I guess I didn't look back far enough.The sizes you list are certainly the closest to OE rolling diameter. I can tell you that a 19x9 with a 45mm offset will not rub on the front running a 255/35-19. On the rear, 19x10.5 with a 60mm offset will not rub with 295/30-19. Some people prefer a tire with a little more meat on the sidewall. Anything below 3% is acceptable on the IS-F.
I called HRE today to try and figure out what they recommend. They recommended those same sizes, but said that the exact wheel backspacing was proprietary information and would not be given out.
When you said that these sizes won't rub, did you test them under extreme cornering with max body roll? Also, if I went with a coilover setup later that lowered the ISF by about an inch, would these sizes still clear without any rubbing?