I am enjoying my analog system, but what can I do to improve?

Check any music frequency chart. There is no music up there to hear if one even could and the gear is capable. Just noise most likely. Waste of time and money but if you’ve already conquered what does exist and can be heard then there has to be something else to obsess about. So the whole you need a supertweeter to hear what’s not even there argument is shooting blanks.  If you use a supertweeter to tip up your subtle top end for more air than otherwise, different story. 

Look into an Ultrasonic Cleaner...

Used as a primary conditioning tool for your vinyl and in conjuntion with other brushes and cleaners periodically thereafter, you can enjoy your records more.

Initially, clean your records with the ultrasonic, use a vacuum cleaner (VPI, etc...) or manual bath machine (Spin Clean) to rinse and dry and a (Carbon Fibre) brush for every day use. Plastic sleeves for the albums and Mobile Fidelity Inner Sleeves (or the like) for the discs. The improved sonics of a clean record are an under valued asset.

Once you know how the records actually sound, you can begin to hear any changes to Arm, Cartridge or Wires.

Hanging around an ultrasonic RCM may require use of super tweeters!

Ray Kimber of Kimber Kable had a frequency spectrum analyzer app on his smart phone at one of the Audio Shows which revealed the incredible high frequency (ultrasonic) noise those excellent machines can produce. Caution is in order!

a dipole in a ten by ten box, surely…not…

refresh my memory, you had a Brinkman, Sota, etc thread going awhile back ?