When installing the top hats on the KWV3's, how many of #6 do you use for each tophat?

Is it one underneath the mount and one on top, or just the top one? I haven't been able to find a clear answer of this:

 

Two per strut or side. one up one down.

4 for the front.

 

And which parts should I replacen when installing the KW V3?
I mean, I already dissamble the whole thing, might as well change the parts that might be worn out after 15 years.

I thought I would need to other:
2x #6
1x #7
1x #9

 

The rubber bushings are metal reinforced, there's no need to replace them. I'd replace 9 for sure though.