Ok, next problem is that the screw holes in the bottom of the casing weren't going to line up with the new ballast, so a quick drill job and the new ballast had a good solid seating:
I had a little hesitation about the wiring (didn't want to ruin anything)... some quick research and online advice and I think I have it all straightened out. The power comes in to the fixture, through a switch and in to the ballast (simple, white-to-white, black-to-black) - then the wires come out of the ballast as red and blue, BUT the wires up to the lamp were red and white.... apparently it does not matter which way you do it, so I went red-to-red and blue-to-white. Quick test - it works, so I am guessing it all right now.
I was put off by the electronic buzz it made while lighting off, but that only lasted a few seconds and the thing went dead silent. I will observe for a few days before I make any final judgements, but so far, so good.
Here it is ready to close up:
and next to the old ballast:
all closed up, and this thing is noticably lighter. I will be curious to see how much heat it puts off.
I also just swapped out my 10k Aqualine for a 20k from the same company - Not sure if I like it yet, I am going to let the color burn in a bit. More pictures soon (probabaly)