Writing a Formula based on UserForm input

I've attached a sample of the data. The formula I'm writing needs to go in column K, Best Price (=max(investor1, investor2, investor3...) whatever investor user chooses for that product.

To determine which product, I need it to look at the code in Column D, Loan Program. I was thinking of using the Left function to look at the first letter in the code as the term can vary. C= conforming, F= government

I do already have a userform created.

Left column, Conforming:
CheckBox1: Investor 1
CheckBox2: Investor 2
CheckBox3: Investor 3
CheckBox4: Investor 4
CheckBox5: Investor 5
CheckBox6: Investor 6

Right Column, Governent
CheckBox7: Investor 1
CheckBox8: Investor 2
CheckBox9: Investor 3
CheckBox10: Investor 4