There is no need to tie down the suspension.
If you have a flexy suspension and decent body weight, you will be
much happier at speed with susp tied down, especially over really
crappy portions of a highway.
I used 8 straps (10K working load each), 4 to body and 4 to axles.
Obviously, my body weight is much higher than most EB's.
Have had my body straps crossed as shown for over 20 years.
Never had and rubbing or cutting issue. Maybe I just have
much higher quality straps. I do crank down on the body straps
really hard, to the point of pulling susp down 3-4" at least.
Also depends a lot on trailer. I bought a new alum 26' trailer.
Was planning on ditching deckover shown, but that thing was
homemade, with 12", 1/4 inch wall C-Channel frame. Super stiff
and pretty short. Tows extremely solid, even @ ridiculous speeds.
My alum trailer has a decent amount of flex, comparatively. I'm
keeping that deckover for shorter day trips.