Is the motor on your Wilson turntable directly underneath the platter? What I have seen some do in the past is to place a thin sheet of aluminum foil underneath the turntable mat. This will create a shield in-between the cartridge and the EMF fields being created by the motor.
This is ineffective if the motor of off to the side. But if it is directly underneath, it may be an inexpensive way to create some shielding without breaking the bank.
This is ineffective if the motor of off to the side. But if it is directly underneath, it may be an inexpensive way to create some shielding without breaking the bank.