ZT wheels can suit the 75 well, we've put 18 inch 11 spokes on our 75 which really suits it I think. Just bare in mind changing up from 15inch standard classic wheels to 17 or 18 inch will make the ride slightly firmer. It's still very nice and wofty though. We didn't really notice any change as we changed up from 17inch serpents which use the same profile size tyre.
suzublu has the same wheels on his mki which really suit imo.
17inch starspoke wheels which were fitted to the mkii contemporary models really suit the mki 75 as well:
Have you also considered the 17inch meteor or serpent wheels which were the top of the range 75 wheels on the mki's and were also available on mkiis?