SBA+conventional clarification

I have a few gray areas in some of my notes that I'm hoping to get cleared up.

Let's say you need to borrow $7M and an SBA qualified lender that offers an SBA + Conventional option.
1/ If the SBA rate on the initial $5M is 10%, what would the ballpark conventional rate be on the $2M? How much higher should I pencil in?
2/ With the SBA on a 10-year amortization, is the Conventional portion, the $2M in this example, also on a 10-year amortization or is it typically 7?
3/ If they are pari passu, and assuming the Conventional rate is higher, am I able to paydown the Conventional first (with any cash flow after required interest/principal payments)?