I do about the same - I do all of the winterizing myself except for the engines, which I let the marina do, since as well, I figure it cheap insurance, and I am not that comfortable with doing it myself.
After blowing the lines, I found that I had to pour at least 8 gallons back in to fill the hot water heater above both lines before anything would flow through the hot water side.
Even after blowing the lines with a compressor, I bet I got a half gallon of water through the lines before the pink stuff, so I am not sure how good the compressor does.
I am thinking of putting in a bypass system so that I can tie the hot water side to the cold water side, bypassing the water heater when I winterize next year.
For the A/C, I put in a fitting so I could put a hose on the A/C just before the pump. Turn off the seacock, turn on the A/C, and pour a gallon of pink through the hose on the fitting.
The sump, I simply poured a gallon of pink through it.
For the electric head, I filled the water tanks with a couple of gallons of pink, then ran the head until I could see pink flowing through it.
Unfortunately, this took about 14 gallons, with most used up by the heater. If I can bypass the heater, I think I can get it down to maybe 4 or 5 gallons.
Anyone have any different techniques?