Most sidewalls say 42 psi, and I have to think the profiles were designed around that. You will find different manufacturers have different profiles, and why they handle differently. The old BT-021 for example was a soft tire with a a very round profile and definitely very difficult to get that tire to turn in... hated them. They were OEM on 2010 FJR's AFAIK
To me, when I looked at 190's, the profile is proportionate to 180's, as long as you're using a 190 designed for a 5.5" rim.
Who has the largest contact patch? Does it matter... the differences are very small and you'll only test that in extreme conditions such as rain or on the track. Compound choice affects that too, a harder compound doesn't have as good a grip and that is far more important to me, so I shy away from PR2's and RS3's. OK for a touring type rider though or in warmer weather or if you're going on that long trip.
Back in the day when I ran what Russ is running, one might think the contact patch was smaller, but the compounds are softer than most m/c tires. They stick like glue, yet will last forever (except Hankooks).
If you want to roughly measure your contact patch, find some nice smooth paved parking lot, ride through a puddle and lean in. Back in the car tire days, some did this to compare to m/c patches...