Howdy Toufu,
1) go do some resonance checking on:
http://www.resfreq.com/resonancecalculator.html
2) It could just be that some added weight (but VERY little) could be of some help.
That could be if your arm resonance is out of the acceptable band (too high, my best guess).
3) And there's another suggestion entirely, but I promise it will work! Consider the use of a Step-Up transformer, my best guess is, your phono-pre does not have such.
Your cart has 0.4mV output so it can work with a low ratio trannie. Around 1:12 to be on the save side, 1:16 could still work without risking a phono-pre overload.
It will give you a number of benefits (not pocket though!) and reduced groove-noise is one, appart from greater dynamic range, detail etc. I've done it, so I speak from experience (mind, I don't sell any of the stuff either).
I tried my darntest to get reduced groove-noise, - I clean my records with a Hannl-MERA (best I know of). Only since having gone with an SUT can I say it is acceptable. A lot of groove-noise happens in the very high frequency band (Ultra sonic band) and what you hear are just the lower sub-frequencies/harmonics of all that pop and crackle mess. A properly set-up SUT will take care of a LOT of that, but of course not all!
Take care,
Axel