Help with TT for my System

I have also ordered KAB's liquid damper after reading (skimming, rather} a very long review in these pages. The person who'll be hanging the cartridge is also of the opinion that the damping kit should ameliorate and resonance issue with the factory provided headshell,  and I should not spend any additional money on a different one.

I miss my Teppaz!

The advice is certainly going to produce music as a End Sound in any configuration, Damper - No Damper - Factory Headshell

To suggest that a Headshell is not to be exchanged is very opinionated and very limited to what can be experienced and more importantly what can be attained. 

There is the individual, who has their own unique preferences for how an End Sound being produced is able to impresses them.

A simplistic method to make investigative inroads to learning is a exchange of a Headshell, where for multiples of individuals, this as a method has proven to be a substantial step towards attaining the End Sound experience that really satisfies.

Is the expert advising on the TT Support Structure and how the TT is mounted on it?    

If you're going to invest that much in a turntable, a better headshell can certainly be a good investment if you have a resolving system, which it appears you do. It appears that the 1200G headshell includes one important feature that many headshells don't - azimuth adjustment.  Having said that, a headshell that handles resonance well and has better connectors and wiring can make a difference.  I personally like the LP Gear Zupreme headshells, which are made by Jelco.