how long is your 6I ?

If you're holding the club at the same position relative to the head there will be just a minuscule difference in swingweight due to the loss of mass that used to be above your hands. That mass was so close to the fulcrum, I doubt any human would notice the difference with all things being equal. With that said, it's not really possible to keep all things equal since you will be gripping it with fatter part of the grip as has already been mentioned. The difference in grip position/feel will far outweigh any change in the swingweight*.

*relative to where you have been gripping the club

He's pimped other offerings from that company before, right? Seems perfect.

In addition to, and perhaps more important than, swingweight changes.....

With length changes that dramatic the lie angles are sure to require modification.

I've never attempted single length experiements myself so I cannot comment much on its affectiveness.  But I do know that the traditional way clubheads are built is centered on length changes in the set - minor increases in clubhead speed, minor descreases in shaft flex, etc. to match the clubheads loft and center of gravity for proper launch.  Monkey too much with one variable and the result starts to change.  Basically, you're setting yourself up for a lot of equipment modifications in addition to cutting a shaft shorter.

But hey - experiment away - I love it when someone else offers to be the lab rat 

definitely i was hitting straight and right  no lefts in the mix.  will take a while to really having to work to turn the head over again