Another vote for Canyon Dancer straps. They work great. Mine also have that soft protective cover across the middle, but it doesn't actually touch anything. I'm not willing to secure my bike in any way that lets the straps touch any shiny parts of the bike.
As to compressing the forks, I compress them down pretty good, working side to side, back and forth a little at a time until there's not much play left. Then when driving I watch the bike on the trailer in my mirror, and if it bounces more than about 1/2" I stop and compress them a little more. I'm not crushing them or hurting anything ... hey they're made to compress (picture guys doing stoppies) ... but to me bouncing around means a strap or hook could pop loose or break.
Next time I'll try to remember to measure how much fork is still showing when I have them secured.
Oh, also, sometimes I see crazy basterdz using only 1 strap on each side on the front to secure their bike. I just can't do that. I picture a strap breaking and lots of easily avoidable damage. I have a box of various ratchet straps and bungees, and I use a bunch of 'em, front and back. If any one of them breaks, I probably won't even know it until I go to unload the bike.
Good luck!
=x+rap01a+0r