I'm with myself regarding drilling holes in the cylinder barrels. Total waste of time doing this kind of thing. I'm old school and do just about everything without asking anyone if it will work, but this is one thing I would just never do unless I was making some lawn art. Different drummer that I am.
I have thought of fitting aluminium barrels because of the weight of the cast iron ones. But for me, it would be a backwards step. The Commando motor is excellent when it runs on methanol. It can probably be made to go just as fast on petrol, but that would involve ten times the tuning work.