Were there any papers that came with the new units? I'd suggest starting there. Hopefully there would be some instructions in it to address proper installation.
I only did mine about 6 or 8 months ago but am having difficulties recalling exactly how it went, but they came out shining right where I think they belong. I saved one for the adjusters and such and just went and looked at it, actually it has 3 attachment points, only two of which are adjustable. One on the bottom is only a support with a rubber nub that sits into a mounting hole and the two top ones are adjustable, but should not spin, even tho they are designed to swivel. I'm not sure if my new lenses came with both adjusters or not, but I did have at least two left over. I simply can't remember exactly how it worked, but I know they came out doing well. Hopefully you'll find something that came with your new ones that will help resolve this for you
Edit again, the adjusters are set on the mounting bolts. I took mine from the factory and measured each adjuster and set the new ones at the same place, then slid the unit into place and put the mounting nut on and tightened it down