The first problem I encountered when mounting my E450 Givi backbox onto the rack, was that I couldn't open the lid without unclipping the box from the rack first.
My 'fix options' were either (a) mounting it further back, which made it rather unstable without some sort of rack extension (which in turn would leave a huge gap between the backrest and the box); or (b) mounting it higher. At least if it was higher, it would be tighter to the backrest.
I went with the higher route, and got a pair of rack extension brackets fabricated out of stainless steel.


As you can see here, I could have gone about 1/2" higher to clear the backrest completely, but as it is it opens far enough to get our helmets put away easily enough.

As for the light question, there is a built-in housing for an extra stop light which is an extra from Givi. The picture doesn't give it much credit, but it is very bright.
