verdict?
is pissin down atm so only took it round the block, but yes, very much improves the acceleration.
indeedly.
a worthwhile mod imo
hopefully it will dry up a bit for tomorrow so i can give it a proper thrashing
dyno next - sort the lumpy fuelling out & away we go
in case anyone cares, and fancies doing this - here's the dimensions.

the ring that holds the starter gear is turned down to 120mm (any less will go into the screws)
the outside diameter turned down to 136mm (any less and it will burst through - that leaves 1mm)
height reduced to 62.5.
you can go a lot lower but it will expose the magnets and cut into them - not a problem tbh as it will still make leccy, but there is a 8mm gap between the magnets that will need to be filled.
i used araldite, flooded the holes with it and put ally tape over the top, then as it was curing i left the bike ticking over to balance it out
the one that is still at the machine shop, ive asked him to leave the height as it is and leave a 2mm step on the outside diameter so i can keep the timing marks.
i'll add a pic when it comes back.
for the sake of losing another 10g i'd rather keep the timing marks so i don't need to swap the flywheel to check for tdc.
it feels a lot smoother & less vibration than with the original rotor - but looking at it, it had been touching the stator in 2 places so it was obviously bent, either from when i crashed it or from a previous owner.
tip there - be carefull never to drop the flywheel / rotor as it is acyually quite fragile - even more so now that it is only 1mm thick lol!
