Measurement of rain gutter

Does anybody happen to know the measurement over the top from rain gutter to rain gutter??? I am building a rack and need to know the distance so I know where to attach the gutter mounts to the rack. I am making them adjustable, I just want to get them as close as I can.

Just took the measurements earlier today actually... Gutters are 54" wide, roughly 77" long (maybe a hair smaller - measured usable length). The gutter width is based on the inside edges of the factory roof rack rails being 45.75" apart, with the inside edges being a hair over 4" away from the gutter.

*EDIT* Holy dead-thread resurrection, Batman... I was looking for gutter mounts and found this thread. Oh well, someone might find this info useful.