Trailering
First a very basic rule and one which is sometimes overlooked.
PUT THE HEAVY END FORWARD!!! Although the Z06 is pretty neutral 51/49 you still want the front end forward.
Secondly, you may have to use some extended ramps or put the ramps on a 2x8 piece of wood or series of "steps" to keep it from scraping either on the approach to the ramps or as it enters the trailer bed. (One trick is to use the trailer jack with the hitch still attatched to the tow vehicle and raise the tongue to decrease the approach and conversion angle.) A trailer with a beavertail helps. You may also want to consider removing the front outboard spoiler pieces and even the center section if necessary.
Now on to your real question, tiedown. I assume you have some sort of "D" ring on all four corners in the floor of the trailer. Attatch your ratchetting tie down straps to these and the FRAME of the Vette. DO NOT attatch the car using suspension pieces. Some use "T" hooks and use the slots in the frame used by the factory for initial shipping. Some cross the tie downs to the opposire side, others don't. I always use a loose safety chain as well...even in an enclosed trailer. I saw the gate fall on an enclosed trailer and the race car came rolling out the back as the truck left the race track gate,.... the driver didn't even realize it until he was 2 miles down the road; when he finally looked in the rearview mirror and saw the sparks from the tailgate door dragging. We all were waiting for him as he came back 20 minutes later red faced to pick up his car. Just think what would have happened on the Interstate.
Which brings me to the next piece of advice. START TOWING SLOWLY at first. Trailer/Tow Vehicle dynamics change with speed, road conditions, pavement, weather and temperature. Check everything twice and then again. Check everything all over again at each stop: Tire pressures, tie downs, safety chain, lights, brakes, hitch, transmission fluid. Be Paranoid!!
Above all make sure the hitch, ball, hitch extensions, tongue and trailer are all properly certified for the weight you are carrying.