99' Valkyrie/North Central Indiana
I'd say you're starting at 35 psi. is a good point to start. The pressures are Honda stated are assuming you run "Dunflops" 404's IMO. The 888's are a harder compound so watch out for cold and/or rainy conditions. The old 880's were softer compound and 40 psi. was common on the heavier 1100's rear tires.