Seller Subordinated Carrybacks on MF

[Andrew Kniffin]

Hello BP Nation:

On MF transactions, Sellers often will carryback a subordinated note (junior to the bank note) in order to lessen the upfront capital requirements of the Buyer. 

Can someone tell me more about the nature of these notes?  A few specific questions...

1. Do these typically amortize, or are they interest only?  If amortizing, are they usually ~25 years?  More?  Less? 
2. What is the interest rates on these?  ~7%
3. Do they 'balloon' at 5/7 years?  I can't imagine a Seller wanted to hold my note for a full 30 years...

I'm looking for *typical* information; I understand that this will vary.  I'm seeking 'ballpark' info so that I can structure offers in a realistic way that maintains/builds credibility. 

I'd love @Joel Owens 's input, since I've always valued his input and experience-based market insight.  Thanks to all!