Leon,
I'm going to take a guess and say you mean "lugging" instead of "lagging", because one thing an MC shouldn't do is lag.
Since the MC has no primary balance weight, I'd definately go with the 14 oz for technical rock riding. The 14 oz works very well, and there is a noticable difference between it and the 10 oz., more than you would think. I think this is due to the way the 14 oz wraps around the edge of the flywheel (greater dia. and MOI).
See this article:
http://www.gasgasrider.org/html/flywheel_effect.html
You should not need a spacer for the cover. My '00 needed double gaskets but I do that anyway for better cover sealing.
Not sure if you can get an E-Line lighting coil for a GG. I think it would be eaiser and cheaper to just get the 2K-3 EC ignition flywheel/stator for 75W, or the 2K-2 for 35W, depending what you need. You could use the Ducati Energia from the '98 (assuming you have one) but you have to fab a special ignition cover adapter to use the '98 cover on the newer cases. Kent A has done this, do a search.