You just need more practice water starting and uphauling a 100 liter board. No doubt it will be easier to uphaul the 107 than the 97, but the 97 will provide a lot more fun and control in windy conditions.
I get the 80 liter issue for strong winds, but where I live, I also have highly variable lake wind conditions. Today it is forecast to blow up to 30 knots, and I just loaded my old Tiga 263 (80+ liters?). When we have winds to 30 knots, there will be 10 knot holes and I have a wind shadow to get past (100 meters) with today's wind direction. Generally, I end up on my HiFly 105, simply because it is really tough to get through the shadow and holes on the Tiga. If I go down, then it can be a long time before I can water start.
In Misho's situation, he is being EXTRA conservative because his water starting and uphauling skills aren't yet refined, but he needs to push it a little to move to the next level.
As Waiting for Wind said, the Futura may be a better option than the iSonic. A little slower for the advanced sailor, but possibly faster for the intermediate sailor, and certainly more user friendly in the chop. For an intermediate, it will take quite a while to master the iSonic compared to the Futura.
Formula 160; iSonic 111; HiFly Move 105; Tiga 263; '85 Mistral Superlight.
Maui Sails TR 11.0; 9.2; 8.4; 7.6; 6.6; Maui Sails Switch 6.0; 5.2; Maui Sails Global 4.5; 4.0.