Here are the home specs

Appraised 1,400,000
Purchase Price 1,050,000

Home is going to be finished being built in the next month.

I know the owner/builder. He will carry the whole note with 400k down. He would be carrying 650k for as long as i need at 7%.

I have 200k and thats all i have. I need a partner or maybe a second mortgage? idk. I cant get a loan from a bank so what are my options?

Also does PMI work on a second? Or can i have the owner/builder put on paper that in the case of a default he would only get what is owed to him?

I was also thinking maybe something on paper saying in case of default the second gets the home? But the owner/builder has the option to pay the amount in full before?

I mean a second really has nothing to lose on this deal. they will get paid a lot regardless of what happends. Any help or ideas would be welcomed thank you.