If you started at 6 o'clock, then I'd wager you're ~20% power. If this is the case then you are hitting at ~40-50 watt peaks. That's a lot of juice for the Fortes. Not saying it will hurt anything... but it might hurt my ears if I was in the room. Rock on with your socks on Frah!
I'm not certain of the ~20% or so power output. The SX-1980 (or any of my other audio gear) does not start at the 6 o'clock position, but around the 7 o'clock position. Not a huge deal obviously, but just a minor detail.
I have an Accuphase power amp that displays output wattage, and when I play music at similar levels as the SX-1980, it seems to rarely get above 15 Watts.