Two people, two months, zero built?

Bikeshedding is piping up on trivial issues to draw attention to yourself in a group. There's only two of you? You should have enough mutual trust such that nobody feels the need to show off.

I'd suggest putting a stop to any more design meetings. Get a prototype working, iterate from there. What needs to happen will become apparent. It's all smoke and mirrors in the beginning anyhow. Take a page from the Italians and their fancy A-GEE-LAY methods.