Career corporate financier and banker, specialist in advising on equity and mezzanine fundraising in London (including public markets, particularly AIM and NEX), private equity/venture capital, trade finance, asset based lending and the developing areas of crowdfunding/peer-2-peer/ICO. Experience of most industries, including technology, natural resources, services and manufacturing. Skilled in putting together creative solutions to difficult situations, including restructuring under creditor pressure and difficult jurisdictions. Advised on numerous transactions over more than 30 years, including IPOs, reverse mergers, secondary offerings, restructurings, working capital refinancing and long-term debt.
I think you first need to answer the question how key this individual is; if they are the difference between making a success or not of the venture then you should be generous with the quantum. Your own historic investment can be protected through reflecting the amount using a class of preference shares. I don't think you can expect him to work for nothing and buy in at a full price for a business that is not currently producing revenues, but you could vest based on various milestones.
It is possible for a company to issue different classes of shares with different voting and economic rights. You could structure the equity for the new management to have restricted voting rights and for their returns to cut in only once your shares have delivered a certain level of returns.
The first matter for you to conclude is to agree the terms of a shareholder agreement between the two founders. This shareholders agreement should govern the management of all significant governance matters. Without this you will subject to the constitution documents of the company and local company company law. This is a standard type of agreement that any decent corporate lawyer will be able to advise you on.
As the voting shares are held equally, then no major changes will be able to be made without both founders agreeing to the changes. The non-voting shares (assuming all other terms are the same) will have equal rights to financial returns (dividends and liquidation rights), but will not be able to participate in voting issues. In simple terms, you will have an equal say in the running of the company with your co-founder, but will receive 25% of the returns, while they receive 75%.
OK, first a general observation. I believe we are still in such an early stage of equity crowdfunding, that is difficult to know how things will even out. VCs and stock exchanges have had plenty of time to work out pricing norms and models. At the current time I believe you are just as likely to get a high valuation as a low one, or none at all due to a failed raise. The lessons from the internet industry to date is that it takes a relatively short time (2-5 years) for a dominant platform to take route; think eBay and Amazon. To date, a dominant platform has not yet taken hold, but it will come.
Now in relation to your specific scenario. The advantages of equity crowdfunding is primarily that of availability. If you have a seed stage business the options for external capital raising are generally thin on the ground, and if you do find a VC to fund it, you will probably get a very tough deal. Crowdfunding, like any public market equity (and let's face it, equity crowdfunding is just a variation of public market equity within a new online context), provides a way to access capital while existing management retain control and have no dominant external party.
Will you get a good valuation? No idea, but the you will probably get a higher valuation that a VC will give. the question is probably more one of whether either Crowdfunding or a VC will fund at all.
Once you have a successful crowdfunding round, the key is to communicate with your shareholders. This is not a fire and forget exercise, and they will not wish to be treated like a parent you just go back to for money.