You can go to our website, https://sites.google.com/view/communityfleet, to see what we do as far as rating. I wouldn't say that we "invented our own" as the system is essentially 90% PHRF, 8% PYS and 2% for what seems to be our unique adjustment of the B Factor in a ToT calculation. We give different boats different ratings and different B Factor adjustments depending on wind conditions. That does eliminate the issues where F18s are better in some winds and the opposite in others. We do this because we have a very diverse fleet where we are racing trimarans, monohulls and catamarans (older and newer designs) all in one fleet.
If we were exclusively catamaran populated, SCHRS would likely be the ticket. That said, some of the SCHRS ratings that define a speed differential between some boat models are not consistent with the many years of racing history we have. I am not saying wrong or right, just that our experience is different. In the end, any system is only as good as the buy in you get from the racers. If they don't race because they don't think it is fair, it won't take long before your fleet just goes away.
Blade F-16 (2nd One)
This has sort of become two different conversations...
Regarding the N20C/FCS sails. I just got my boat last month and can't report on sail longevity yet. I bought it used and not know how many miles the sails actually have on them, but... they seem to have a bit more wear that we expected. If I had my choice, I'd buy sails from Landenberts, 1D, NexGen or Glasser, but class rules currently limit that.
For SCHRS, you are correct, sail material has no impact on rating. However, SCHRS makes the assumption that you are class legal. If your boat doesn't meet all of the class requirements, you can't claim the class rating and need to be measured.