Tim,
Sinharavi candidate is only asking for 231 USD, so I see no risk at all to try it with him.
We already have the funds to hire another developer too, in case that he fails. Yesterday another company from India made an offer and they were chatting with me, they look very professional and acting like that, they quit to study it properly and give again a right offer.
In fact I don't think that any of them will fully complete it, but we will do it once we have a valid skeleton that builds fine from Visual Studio and once we publish it as open source