I am checking in to say that investments of this kind are,imo, not properly filled by custodian proposals.
The norm, is that custodians proposals are meant to grant NuBits to fill a market need .Custodians sell them at 1 USD in the open market.
Crowdfunding / crowdequity / donations are the way to go for such projects, imho. see Swarm, or Lighthouse if we want to make it crypto .