odd request for measurement

[christyf5]

Hey guys,

So a buddy of mine is building me a light rack and is about to drill holes for the VHO mounts. They're just standard waterproof end caps.

Thing is he's worried about the "exactness" of mounting the end caps. Do any of you guys run 6 foot VHOs? I know I'm living in the dark ages and should switch to T5s but these are good enough and I like to spend my money on other stuff

So if I could get a measurement from screws to screws of the endcaps that would be awesome. I told him it added about 1/4" on either end but apparently thats not good enough for him