which filter for 12-24

Just bought my D300 body at Grays of Westminster in London - fantastic machine - though the usual whine about us Europeans having to pay $500 more than the USA etc.

Anyway the main reason for the post is that I'm off touring Australia for the holiday season and want to get a split ND filter for my 12-24 Nikon - ok so 77mm lens screw is bad enough, but the only decent set of filters for the lens seems to be the Lee filters (as they do a special wide angle adapter). So the other problem is the size of the ND's ie 100x150 - too big for a backback holiday !! OK - so clearly I'm not a dedicated enough photographer and don't want to suffer for my art. Has anyone used the hitech 85mm filters or does anyone have a better suggestion than blu-tack?