Front strut installation

[NaughtyLuvJungle]

Hi all, general question about installation of the front struts in my 2012 hatchback SE (130k miles). Last year the passenger side strut mount got flagged during annual state safety inspection. I decided it was probably best to just do both struts while I had everything apart anyway, so I put in loaded struts from AutoZone.

After putting everything back together & passing state inspection, there was a rattling noise from the passenger side that sounded like it was coming from the strut mount area. So I took everything apart again, inspected, put back together, no change. Thought maybe the new strut was faulty -- took everything apart again, warrantied out the new strut as defective for another new one at AutoZone, put everything back together -- noise still there. Replaced the sway bar link -- noise still there.

Took into reputable local shop, they checked everything (ball joint, tie rod, etc), can't find anything. I also browsed these forums and read about the control arm bolt issues.. i don't think it's that. I give up and drive it for a year.

Now last month, the other side on the front starts making a very similar rattle noise from the strut mount area. I take it to a different local shop and they "tighten up" the bonnet nut on top of the tophat-looking circular disc above the fender on both struts. (Not sure what the proper name is for that part -- the disc that floats advice the fender wall when the car's not on jacks). The passenger side noise goes away! But not the drivers side noise... It's driving me nuts

My question is, I am wondering if anyone can give pointers on how to properly install/ adjust the struts mounts. When I first installed these new struts I counted threads on the old OEM ones I'd taken out, and adjusted the bearing nut on the new strut's threaded rod. (To make sure everything was set exactly the same on new vs old struts). Then installed the strut and tightened the bonnet nut at the very top, to jam the circular tophat disc thing against the bearing nut.

But maybe instead i should have set the car down first, and loaded the springs, then tightened the bearing nut even more from above the fender? (Before installing the tophat disc thing?) Opinions would be greatly appreciated, I'd really like to not have rattling suspension. Thanks in advance