Warwick Potiknob Tandem Metal 2 G

Bought 3 sets of those Tandem knobs to replace the worn out ones on my 20 years old Warwick Fortress Masterman. This might be one of the most dissapointing installations I have ever done. One of the knobs was missing its screw so I used the screw from the old knob. Then I discovered that screws on the new knobs are totally useless. You cannot completely tighten them because they are not the right size for the threads. They are thinner. So I had to use the screws from the old knobs (Thanks god they are compatible with the new knobs) otherwise I'd be left with useless junk as I cannot send them back to Thomann from where I live. Most interestingly there was a one screw which came with the new knobs; gold colored, pointy tipped. I t did its job perfectly. Seems like Warwick had screwed on this as they try to reduce the costs.
Second issue: Probably Warwick has changed the bore dimensions on the knobs slightly since my bass was made. When you install the new knobs they cannot operate independently. That is; when you turn the top volume knob the bottom balance knob turns with it too. Leaving space between two knobs also did not work. Then I discovered I had to leave some space between guitar and the bottom knob. Now it workb but I did not like the feeling of the bottom knob kinda hovering.
Eventually it works but leaves a bad taste...