If anyone wants to do a simple experiment on how loading affects a magnetic circuit, one can use a speaker. It’s similar to a MC cartridge circuit wise as the coil of a speaker moves in a magnetic field just like an MC cartridge.
Start with an open circuit (speaker disconnected from amp) and lightly push the woofer, it should move freely. Then (as an extreme example) try wiring a jumper across the + and - terminals of a speaker (make sure the amp is disconnected). Try pushing the woofer, it will resist all movement. Then, try wiring a resistor at 10x the impedance of your speaker. You will notice some resistance trying to push in the speaker compared with the open circuit. Then try a resistor 100x, then a 47k resistor.
This will demonstrate how loading affects the effective stiffness of the cantilever under various loading conditions.