I have not tried the double rack or put 2 bikes on the NSX.
I first tried not having the front portion of the rack (with the 3 suction cups and quick release) on the roof and put it on the rear glass. This way the bike was facing backwards. But, the problem with this set up was the rear cup was on the front windshield at a very steep angle and there was very little contact with the rear tire and the rear cup. I was very worried that even with the velcro strap holding the tire, it would still slip off of the cup.
I then tried putting the front portion of the rack on the windshield and the rear cup on the rear window. This put the bike facing forward and actually worked fairly well. There were no suction cups on the roof, which is what I would have prefered. I was worried about restricted view out the front window with this set up but when in the drivers seat you could actually only see one of the suction cups and it was just below the level of the rear view mirror. So there was no problem there. In this set up the crank and pedals were quite close to the roof line, but there was no contact.
I settled on the set up in the photo. The only problem with this set up is with the bike on the roof the trunk only opens half way, so you have to have the bike off if you want full access to the trunk. After the race I took the rack off the roof, washed the car and there was no marks or indication that there was ever a rack on the car.
I think for my next race (on the 24th) I will try the second set up with no suction cups on the roof, all of them on the windshield and rear glass. I still think this is the best way. Even though there were no marks on the paint from the suction cups I would still feel better if there was nothing touching the paint, period.
This is a fairly expensive system. But the quality is fantastic and it is unbelievably easy to mount and take off. They even give you an extra suction cup with your order. It is made in the USA.