I have the P300 as well. I started out by running an Xtreme Statement into a HC/UO, then another Xtreme Statement to the P300. Plugged in to the P300 were my tube preamp, CD transport, DAC, and tube phono stage. I only used the 60/120 settings on Sin wave. I never really used the Multiwave options, at least not to this point. I think the system performs well, but the fan does come on after about 30 minutes and the P300 still runs hot even though its on an amp stand not the floor.
Today I reconfigured. I run the P300 from one wall socket with only the CD transport, DAC, and tube phono stage connected. The HC/UO is in a second wall outlet with the tube preamp plugged into it. The tube amp has always been in a separate wall socket with the power filtered by a Chang Lightspeed (soon to be Running Springs Duke).
I am going to play around some more with the Sin wave settings. If any one has any suggestions for me to try I'd be interested in hearing them. I also upgraded to Multiwave II+ and I like the Clean Sweep demag function. I would recommend the upgrade and it's pretty easy to do yourself if you exercise some patience and follow the instructions.