Well I'm with ya on that one, being that I am 6'2" and my calves run 17", so very similar. I think the biggest problem is not cadence but aerodynamics. Personally to avoid the serious drag problem I have created special cycling pants which have a foam wedge on the front and back of the calves, the upper legs are at enough of an angle to give downforce for the corners so I dont aero them out. Plus I find a 6mph speed boost by attaching a road cone to the front of my helmet, be sure to cut off the square base and a couple holes to see out of though.
no in all seriousness though, I am a big guy too (state above, and I weigh about 230lbs) and my cadence changes depending on my mood and what "feels" (not nessisarily IS) strongest, and I do typically pedal around 90 rpm, I think. If my girlfriend is riding with me I pedal slowly (she's a legs girl)
see what cadence works after 10 miles, if you can mostly hold it that long, thats probably right, OR, just dont think about it. Us bigger guys can *often* apply more torque and power to the pedals per stroke per weight than smaller guys, and often the increased weight of our legs does make slower pedaling work better, but then again look at the track sprinters.... anyone got a high speed video camera to record their cadences?