Just saw your post up above, I will definitely take you up on the offer of a hand with doing the clearances, thanks very much! I was all primed and ready to take a run at it but when I couldn't even loosen the goddamn cover bolts I thought it was probably best left un-monkeyed-with...

In regards to the 'choke' isn't a choke normally a 2nd set of butterflies? This is a separate jet and slide arrangement, one for each carb/pair of throats...