I strongly suggest 51/49. Decision making with a 50/50 split is not fun. Lock-up agreements are generally pretty messy. It's pretty clear you have already pu

I strongly suggest 51/49. Decision making with a 50/50 split is not fun. Lock-up agreements are generally pretty messy. It's pretty clear you have already put in substantial work. I would assume a co-founder would be quite pleased with 40% at this stage.