Thule or Yakima accessory question

I recently got a “Ladder Rack” for my pickup and was looking for saddles for my kayaks. I have looked at the pictures of the various saddles and rollers and such but have a question.

The bracket that attaches the saddle or roller to the bar on the vehicle has a square cut-out to fit the bar. I can tell this from the pictures on the websites. My questions is how wide is the cut-out? The bars on my industrial rack are 1 5/8 inches wide. I would be able to use longer screws as my bars are either 1 5/8 " or 2 1/2 " thick but I don’t know if the brackets are wide enough to take my larger rack bars.

Anybody got some saddles and a ruler??

Budd in far western Kentucky near the LBL