You might be better (faster...shed more weeds) on the iSonic 101 with the Lessacher
Duo vs the Chamäleon.
I have not tried the Chamäleon but I do have a set of Dou weeds (28/32/36/40) and they are really wonderful on the iSonic boards.
28 should be very good with your 6.6 and maybe the 7.8.
Buying a 28 and 32 cm Lessacher Duo's would pretty much cover all conditions you are likely to sail on the iS 101.
Hope this helps,