What year model is your 8.5 m2 Tush Lightning?
Do you have the roller cams?
Are you having any issues keeping the cambers on the mast while rigging?
I looked at the 2009 Lightning rigging guide (there's a .pdf file on the Tush
site under rigging) (http://www.tushingham.com/sails/rigging/2009/lightning
Seems like you need to pay particular attention that the cams are pulled down the mast until the cam and batten are really perpendicular to the mast.
If you let them "ride up" a bit the rollers won't engage and you would most
likely have issues with the cams rotating or perhaps popping off the mast.
Are you in the UK?
Perhaps a call to Roger Tushingham or Ken Black might help you solve the
problem. I've met Roger T. and he seemed the type who wants his products to
perform well and would be willing to help you with tips to get the most from your
Hope this helps,