Oury grips and the plastic throttle tube

Hi,

I got some Oury grips to install along with some symtec grip heaters. The Oury's are quite a bit longer than the stock grips (1cm or 1/2 inch or more perhaps). I'm wondering if I should (a) cut the end off the Oury's to make the the same size as stock or (b) cut the end off the plastic throttle tube and (somehow) install the full length of the new grips.

A couple considerations:
I wear XL gloves and while I never noticed any lack of space on the stock grips, do like the extra room for my large hands on the Oury's. I am thinking of installing some Acerbis handguards in the near future so have to cut the end off the throttle tube anyway.

If I did cut the end off the throttle tube and move the whole thing inward there would then be 1/2 inch of bare handlebar under the end of the grip which probably wouldn't be good. Can you buy longer plastic tubes or could I just find an appropriately sized (diamater) piece of plastic to fill in that 1/2 inch?

Any advice would be appreciated.