Learned today that Strut-Your-Stuff-Here, the ebay supplier of the Columbia brand gas springs in Yakima, WA, also carries offset mounting brackets, but has not listed them.
I just received my 40# struts and also now have my offset brackets from Maxum Hardware. Ready to install soon on my Grandby. I have the full length tracks, 2 load bars, and a factory 55W solar panel up top, no fan (yet).