Securement to trailer

I use two ratchet straps to front k member/welded tow loops/ front axle with straps (depending on which race car). I use two rear axle straps with ratchet straps on the back.
Agree with 67dart273. As short as possible, and always straight.

But my trailer is an open steel bed. I don't have to deal with the difficulties of a wood bed trailer. Frankly, I would weld on tie-down loops wherever I wanted them, and use that.
I wouldn't worry a moment about the tire straps damaging your tires. If a lousy little ratchet strap can damage your tire, you've got the WRONG tires!