From the Manfrotto catalogue I can't make out just how the 350 is actually put together, so can't shed any light on how to disassemble it, unfortunately.
I do have a sort of easier way round the problem which doesn't involve open heart surgery on your tripod, if you're still on speaking terms with the guy from Manfrotto - why not swap the 350MVB for the 350SHMVB, it's midget stablemate?
It's 52cm folded, 49 cm minimum height, 68 cm maximum height and only 4.2 kg instead of 4.9. Everything else is as the standard 350.
That's gotta be a better route than weilding a can opener on yer 350's, no?
http://www.manfrotto.com/Jahia/site/...lsf=68&child=3
CS
PS: I subsequently found a better zoomable piccie of the 350's but still can't see what the leg connect blocks are made of or how they lock the leg tubes in place. If they're plastic, I suspect a simple (but extremely strong) push friction fit. If metal, then some sort of through fastening is likely to be involved. Any chance of some decent close up piccies?