You do know that you have the perfect recipe for disaster, don't you? If you use only 2 straps, you are most likely a danger to everyone on the road, but illegal. I don't know what size tractor you have, but if it's more than a garden tractor, you are taking a
huge risk. Trust me, I know only too well that 2 10k rated straps on the front and rear of a tractor, not even touching any sharp edges, can easily fail on a straight road. I can't imagine how dangerous it is only using only 1 strap on either end. Please tell us that you only have a small garden tractor.
**edit**
OMG!!!

I just read your profile and see that you have a
L5030. That's
exactly the tractor I had on my trailer that snapped 2 10k rated (fine print says 3300 WLL) straps on each end nearly caused a complete disaster. All it took was a dip in the road for the trailer to flex and snap the straps when it flexed back. Many people here have seen the long thread on that incident. Since then, I've
never ever used a strap ever since to secure any tractor to a trailer. If you're only using one strap on either end of that tractor, I'll tell you now, you are most certainly a danger to everyone on the road and are taking a HUGE chance of losing your tractor and severely injuring or killing other innocent drivers.