Hi davori, no experience with this type of mount myself, vibration will be more on a tank mount than a lid mount as your body acts like another shock absorber for the camera.
I’d say you’d probably get a sore neck after a while if you tried to mount this on your lid with a 450d it’d be quite a weight, not sure how the suction cups would perform on a lid either. My lid mount is adhesive not suction - but then my camera only weighs 150 grams.
I only really need it for my euro trip this summer, 450 would be the tank option with the light S95 going on the lid. I imagine I’d look like an even bigger weirdo with a big old DSLR hanging off the top of my head
Do you get more wind noise when you’ve your contour on? Buffeting?
I’ve got the single suction cup version cost about £10 stays on my 'bird at around 90mph just do ALL the screws up really tight and you dont get too much vibration, I stuck mine on the side of the fairing was fine