kz1100-l1 outside diameter of forks with headlight

I have been searchin online all day trying to determine what kind of bracket I need so I can mount me some 3in driving lights on the forks. I believe the items are original (headlight mount and turn signals.)
Driving lights have close to a 3/8" mounting bolts.

You can see lights here
m.ebay.com/Member/G/ViewItemPic.aspx?aid...770836196012&emvcc=0
Mounting bolt protrudes from the lights. I find it hard getting info on my bike sometimes

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I have found the charts already. I do not find the diameter for th.e kz1100-l1. I do not want to guess on size and order wrong clamps. Anyone that has a kz1100-l1 and knows for sure what size clamp I would need to mount on tubes. I read 38mm and 41mm. I don't want the actual diameter, I want to know what size is going to fit. Tubes have stock headlight bracket. Please provide size needed.

Thanks

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From everything I have seen, there is only one kz1100-L1 and its from 83

Let me make sure I understood correctly. I just by a clamp for my tube size and it will fit around tube and headlight bracket with no problem? If correct, i'd love more opinions. Thanks