In my head - I think you're better offering 10% and letting them step into an advisory role - however still requiring them to particpate fully in the presentation (if you don't gain the funds from the incubator he isn't getting shxt, so it would be in his best interest to help secure the funds).
Once that's out of the way, let him step back into an advisor role - and either hire out help with the negotiations/logistics, or spend some extensive time learning that part yourself (courses, certs, online learning, etc).
May cost you a bit more in the start - but once you transition over to the tech-oriented phase and can phase out the additional help or have learned enough to handle it yourself you'll definitely reap the reward from 90% equity split.