I'm the same weight as you. I used Norths in the past and I'm now on KA Koncepts.
Assuming this is for recreational sailing, I think there's the fun factor to consider too. With fun factor I mean how lively, nimble and fast the board feels underfoot.
My two "big sails" are 8.5 and 6.6 (yes, there's a bit of a gap, but it's doable). I used an iSonic 115 with both of those (68 cm wide, so an earlier equivalent of the 107) and they both definitely worked OK. I decided to update the 115 a few weeks ago, but the 107 was sold out and I ended up with the 97 instead. The 97 with an 8.5 is something I can do in a pinch (and I've tried it and it works and was surprisingly lively, but a bit tricky to uphaul etc.
The big difference is the fun factor on the 6.6. The iSonic 97 and 6.6 feel wonderful together, so while I lost some of the light wind range, the 6.6 has been my most used sail this summer and the improvement there was huge.
I'm selling the 115, so for the marginal days when I'm on the 8.5, I've taken my Hypersonic 96 out of cryo-sleep and I'm using it with the 8.5. I bet the 117 would be easier to sail and faster, but for now, I'm really enjoying going back to the Hypersonic.
So, without having tried either the 107 or the 117 and if I was in your shoes, I would go for the 107 because I think it will have a higher fun factor with the 7.5 than the 117. The 117 might be a better choice if you get far more time on the water with the 8.6 warp.
I'm really tempted to get a 7.5, but not really willing to give up the 8.5 either and I want to keep the amount of gear I have down to something remotely reasonable. I think if an 8.0 Koncept existed, I would go for that.