Right, you may be right, I can't remeber I fitted mine over two years ago and its not moved. The longer nut and bolt may well be for teh bracket to attach as it will add a few more MM being in there.
Put it all together in your front room or something first, biggest tip I can give you is to make sure that the joint adapter is the right way around, as I had to re-jig things a few times to make sure that the breather hose was conecting in the right position.
Regards the clips, no, they dont have to be super tight, just firm enoughto hold the filter in place. The engine, when under induction will pull it all togther anyway, it doesnt have to be air-tight, just dont leave big gaps for dust and crap to into it.
I assume you mean the part where the carbon housing meets the adaptor and teh V clip holds it all together.
I laced the inside of teh jubilee clips with some of that sticky sided tape to stop the unit rattleing inside the clip, its also ensures a bit more of a sucure and tight fit.
Is that any clearer?