2 Stroke,
As you said at Maxton, where you have good traction and a shorter amount of track to get up to speed, having a light flywheel, clutch and rotating parts will help you go faster. Different deal at Bonneville where traction is much harder to find. I think that you would find heavier rotating engine parts will help you maintain traction and go faster.
I raced two strokes in the desert a few millenium ago and we found that bikes like the original 400 Zooks were almost impossible to ride in the desert because they had no flywheel weight and the common fix was to add a 3-5 lb flywheel.
I still love two strokes! Jack Costello's little yellow streamliner bike went over 208 with a Honda CR250 two stroke!!
Rex