Strut/hoist for camper shell question

Purchased

$55 10 Pack Strut Channel Trolley Track Hanger Bracket for UNISTRUT P1834-EG 1-5/8 Intermediate Support Hange Bracket for All 1-5/8" Channel Trolley Track

strut hanger brackets to attach two strut channels to the roof of my garage (as well as some trollies for a third strut channel that the hoist will ride on). Hanger brackets will be screwed into the ceiling joists.

Question is, for the two struts that will be attaching with the hanger brackets, it seems like those would slide in the hanger brackets when pulling the hoist/shell. How do you keep the strut from moving inside the hanger brackets while using a trolly or are they so heavy that they just won't move? There is another screw on each hanger that appears to try to prevent the strut from sliding, but it looks like it could still slide. Is that all that's needed?

 

Just looking at it, the horizontal bolt should provide plenty of clamping force to prevent the strut from sliding. Not about the weight, I reckon

 

Thanks for the help!