Selling My Commercial Truck with Owner Financing - Need Advice

I'm looking to sell my commercial truck with owner financing and want to make sure I do this correctly and protect myself legally.

Current Situation:

• I have a small remaining balance that I can pay off to get a clear title
• I have a serious buyer interested in purchasing with a promissory note
• This would be my first time doing owner financing

What I Know I Need So Far:

• UCC-1 Filing to establish my lien on the vehicle
• Attorney to draft proper documents (promissory note, security agreement, purchase agreement)
• Listed as lienholder on buyer's insurance so I'm notified if they cancel or let coverage lapse

My Questions:

1. What other legal protections should I have in place?
2. Are there any red flags I should watch for with the buyer?
3. What's a reasonable down payment percentage to require?
4. Should I require any specific insurance coverage amounts?
5. What happens if the buyer totals the truck or stops making payments?
6. Are there tax implications I need to be aware of?

Additional Context:

• Truck location: New Jersey
• Will need NJ-licensed attorney recommendations if anyone has experience with this

Has anyone here done owner financing on a commercial vehicle? What documents did you use, and what issues should I be prepared for? Any advice on protecting myself from getting screwed would be greatly appreciated.

Thanks in advance for any guidance!