Thanks to the great help of this site and SO, I've been able to make a prototype of a software I want to sell but unfortunately although the prototype works I think my code quality is very low. I didn't use much OOP or design patterns so although my code is understandable to me, I think a normal developer would faint if they had to read it.

So I wanted to hire a developer to make it a bit more better quality and improve some of my implementations of API's that I may have not done correctly. I'm having problems hiring a developer though.

I have met 2 developers and had them read my software specs.The problem is, they lacked my business's domain knowledge(which is completely understandable and no biggie) but they also lacked knowledge of the underlying tech systems I used such as Hadoop, Hbase, Cuda, etc..I spent alot of time explaining map/reduce, bigtables and other technologies I used. I thought it was common knowledge because of my interactions with people on this site but the people I met with mentioned they never had to deal with these things so they didn't know it.

My question is, for software projects that are hiring contractor developers is it a danger if the developer does not have experience with the underlying technologies? or can a general developer who is accomplished in another area realistically pick up new technologies? I did a very very quick back of envelope calculation and I think the upfront costs would be similar if I hire a student or developer with no experience in my technologies who will work many hours versus hiring a highly experienced developer who charges double but finishes in half the time but what other risks should I be considering or worried about? Also, should if I do hire a generalist, should I be paying for the time it takes them to learn hadoop or cuda if they are contractors(seems to make business sense but not sure how fair it is to them if they do not use the skill again).

I'm a bit confused so any suggestions would be great.