I'd suggest any brand of wires that has the spiral core metal conductor. It's a big improvement over the burnt-string conductor.
I'm at 12 BTDC on my 250, and just on a whim I moved the vacuum advance line from ported to full and the engine is a lot happier, especially on the bottom. I haven't checked full advance numbers and I'll revisit it in the spring. When it's 5 degrees outside, I can get away with more timing and still have no death-rattle.
