cool, some good pointers, cheers :D
The hight thing we tried, but didn't work (with the little play room available without drastic changes to guitar)
the oil thing he said, I've not seen it in practice yet, but worth a try with vaseline!
springs shouldn't really be already dead, but it's something which has crossed our mind and may be a solution
As to model, not sure off by heart...tricky thing is it stops just short and just long of the in tune resting point so hard to know what more to really adjust without undertaking major changes to whole guitar....as said, wondering if there's alternative options out there which work?