Should I use the fluid damper for SME 312S

I have a fluid (silicone fluid) damper on my Kuzma Stabi with Stogi S arm. I bought it used locally, and was set up when I got it. The dampening fluid reservoir was way too full when I got it. I had to remove about 4mm of the fluid to be happy with it.
So the level of fluid makes a big difference.
So for you, I would start with the minimum which touches the paddles AT ALL. and see what it does.
Mine the fluid just touches the paddles and overlaps maybe 1mm. Perfect.

Elizabeth is correct.....some cartridge/arms may benefit from damping. Use the least possible ....add drop at time and listen again. If the sound gets better, continue, until the sound field collapses...take out a drop and you're home.

Hifier1958

You posted

I am new to vinyl and am using the SME 312S arm on a Dr. Feickert Blackbird TT. I would like to get some advises on should I use the damper? What are the pros and cons? I have tried every way to get the setting of the arm correct but I still fee that it is not that stable when compared with my previous CD player or my friend's big TT.

I don't know the rest of your system or what the Blackbird and SME are sitting on. Your description of instability could be acoustic feedback but without more information I'm guessing.

I think the SME 312S is a great tonearm and very stable. How would you describe your disappointment and in what way is it unstable ?

Last, I had poor results with damping fluid when I experimented with my SME 312 (when I had it). The phono cartridge would play a role in that result so it may have to be trial and error.

Provide more details, I or someone else here might have a solution that helps.