RE: iSonic 111
At 90 kgs and 8.5m, you won't be far from the practical upper sweetspot limit of the iS111, but considering your desired sail range runs right down thru 7.6m to 6.6m, then iS111 is definitely the preference over the iS122 (considering carrying capacity vs size vs performance etc).
Compared to the Falcon 111, the iS's shorter length won't really be a concern (especially once familiar with the iS character, which might/does take a couple of sessions to really get the most from).
The more tail focused distribution of both volume and planing area in the iS111 (c/w Falcon111) actually assist iS111 in carrying capacity in lighter/marginal/upwind conditions, where the iS delivers a reasonable advantage over the Falcon, without iS conceding top end or control at the other end of the range. Falcon 111 design has dated a little now by modern standards, but fully lit, that Falcon wasn't a board that lacked too sadly at open water top end speed, either..
Net result ; iS111 delivers a more rangy solution, typical of the iS "advantage" against many others. It is certainly not a difficult ride, but also one that rewards extra experience/input with extra performance as well.
Cheers ~ Ian