Front Top Mount Cup Coilover Replacement

Hi All, 

I've got coilovers in my estate at the moment, and I'm experience loud thuds as I'm travelling over pot holes. One of the things I've researched on is the gap between the front top mount cup and the chassis (Photo 1, which is the actual car).

I have read through Bowder1's DIY fix for this using the Polo 6N's cup, cutting the original Cup down, then securing them together using the rubber seal/grommet/sleeve thing (https://www.briskoda.net/forums/topic/308117-how-to-fit-poly-bush-top-mounts/), but I feel that I can do one step better.

I have access to a Waterjet Cutter and a CNC Mill/Lathe; this is what I am planning to do:

Photos 2 and 3 show what I *think* is what Bowder1's DIY ends up being, where the modified Polo/Octavia cup (blue) is merged together touching the top mount bush (red) and the bottom nut (black). The top nut (green) secures the cup.

Photos 4 and 5 show what I plan to do. I know the diameter of the cup and the through I need for the threaded section. I can cut a piece of, let us say 6mm aluminium plate, to form the new 'cup' (blue), there is enough threaded section left for the top nut (green) to sit on top. The only down side i see from this is that the new cup/plate may flex when tightening down the top nut, and the fact that the chassis (grey) isn't parallel with the cup/plate. Would this be a problem if I tightened it down so that it is parallel and touching?

Photo 6 is an addition to 4 and 5 by adding a sleeve (yellow). I am able to make the sleeve separately or as one piece (joining yellow and blue) so that the cup is as close as I can get it to the chassis by machining using the CNC from bar stock.

Questions that I would like answering:

1) Does the 'cup' need to touching the bottom nut and the bushing

2) Is there supposed to be a gap between the cup lip and the chassis

3) Does the rubber seal act as a damper when the suspension travels up and down

4) If the answer to 2) is No; can I fix the 'cup' parallel to the chassis so that there is no movement of the strut

5) Does anyone see any fault in what I'm attempting to make (blue plate in Photo 4 and 5, or yellow and blue combined in Photo 6)

Thank you for reading this far.

Edited 26 April, 20179 yr by HarrisAng
Forgot to add the photo numbers to photos.