Background:
I am looking to acquire a second company that is somewhat similar to my current company that I bought 2.5 years ago. The opportunity for this second business is that it has a really high customer concentration 0f 80% in one customer. They have no long term agreements, and it has not been steady through the past 3 years for which I have the financial documents. The business has been for sale for around 1 to 2 years. Additionally, I have met with the owner and understand that 2 previous deals that went under due diligence fell through. The seller is now highly motivated to sell and understands that it might not be bankable, but doesn't want to go so far as to liquidate. There is plenty of hair on this business that I am not mentioning.

The Ask:
What are some creative deal structures that would mitigate my risk while providing the seller with a reasonable deal they can accept?

My Thoughts:
I do not believe any bank would be willing to take the risk, and the seller confirmed that one of the deals was unable to secure funding through Live Oak Bank. My thought was offering a deal where I put in 15-20% as cash, and then having the remaining balance be a forgivable seller note that would not start repayment for 6 months, and then would be paid based on the topline revenue maintaining a certain level based on the previous quarter. This would ensure that if that customer goes away and I can secure another customer I would not be on the hook to make the debt payment for that period of time.