Incentive Help - Sales Manager Compensation Structure

Hi all, currently running a small company w/ ~$5M in revs. Our customer portf. is small and is entirely B2B which is why we've never needed a sales department. We're now selling B2C products and currently hiring a sales manager.

I'm looking for ideas as to how to structure his compensation in order to make sure he is properly incentivized. Looking at something like this:

-Fixed floor salary
-Phased Incremental variable component based on Quantity Sales targets i.e For every x metric tons sold you get an additional $x amount (Should I put a max ceiling on this variable component?)
-Penalty for defaulting customers
-Sales below a certain price level/unit do not count towards variable component
-Variable $x amount decreases as credit days increase i.e If for every 30 tons you sell you get an additional $1,000, this bonus decreases by 10% for every week of credit given (-10% for 1 week, -20% for 2 weeks, etc..) and if there's no credit you get a 10% increase ($1,100)

Any input is greatly appreciated