Chris, your description of having coolant all over your boot seems odd to me. If your overflow hoses are run correctly, the overflow goes from the radiator to the bottom of the overflow tank, and then from the top of the overflow tank out in front of the radiator through the hose that points straight at the ground. I don't see how that could blow coolant on your boot. Maybe I'm wrong.
I've had odd symptoms in the past where I pinched one of the overflow tubes when I put the tanks back on. The result was that the bike would build up pressure in the radiator, then it would build up pressure in the overflow. At some point, typically in the middle of the night, the pressurized system would blow and spew coolant all over the garage floor. Check to make sure that you don't have a pinched line. I kinda think that's not your problem, but it's a quick thing to check.
I changed my water pump over the winter. The result of that was that a warp in my inner clutch cover developed that allowed the oil passages that run on top of the clutch to leak into the water jacket that is close by. At that point, the oil pressure is higher than the water pressure, so oil was forced into the water, ending up at the top of the radiator as oily sludge. The issue for me became painfully obvious after I did 250 miles at 70 mph, after which I had straight motor oil in my overflow tank.
You mentioned you have sludge at your radiator cap, so think about something like that (clutch cover leak) going on as opposed to a head gasket issue. I thought my problem was head gaskets, and it wasn't. Although we did go ahead and rebuild the top end of my motor, we really fixed the problem just by taking the clutch cover to a machine shop that had a big surfacing table and just surfaced that part. Had I known that, I could have saved $1,500.
All that said, if you find lots of bubbles coming into your radiator on your test, you'll know what your problem is.
Don't worry, you'll get it. Every problem has a solution.