Hi Springy,
As for the bike's being secure on the inside of your B, my installation is quick and handles both mountain and road bikes. If you're tall then check before installing.
I use both height positions depending on which bikes are in; so the floor tray might not work well.
The above Gallery pics will show my bikes installed and so many other great B's and pics.
The wheel locks will not work for the pros but If theft is a problem in your area then you have no choice but to get them anyway.
Keep asking and we'll do our best to give you the right answer.
Cheers, Derek
