All of our tents use standard Metric M8 1.25 hardware to attach to your crossbars.
The mounting plates that go under the crossbars are 6 1/4" long. The center to center of the mounting holes is 5 3/8", so crossbars up to just under 5" wide will be compatible.
The bolts are 1 7/8ths long.
If the bolts are too long or too short for your specific roof rack, head on over to the hardware store. They will have the same size bolts in many different lengths. We do not sell or offer bolts of any different length.