I do NOT like strapping axles or suspension pieces. That's perfectly fine when all is well - the car won't see a lot of fore/aft force in regular trailering - but if something bad happens it's gonna probably break the car*.
I tie my racer 914 in the enclosed using two 5' tie back straps through the holes in the front wheels:
https://www.pegasusautoracing.com/productse...sp?Product=2357Those are clipped to e-track brackets in the floor. I then push the car back slightly to get rid of the slack on those front tie-backs.
I then run two axle straps through the rear wheels:
https://www.pegasusautoracing.com/productde...s.asp?RecID=622...and secure those to the rear e-track via "Heavy-Duty Ratchet Tie Down with 2 Snap Hooks"
https://www.pegasusautoracing.com/productse...sp?Product=2351I use 6-footers because any increase in length allows more stretch.
Edit: *We had a trailer flip on its side some years ago, guy fell asleep (everyone was OK). Got to the scene and opened the back doors...and the two cars were still strapped in place, up on the "side wall". Riggers got the trailer right side up, we opened the doors and drove the cars out. No damage, raced that weekend. We were using welded tie-down points on the unibody chassis.