47 Kohms is the typical "correct" load for MM cartridges.
You can optimize MM cartridges by changing the capicatance, but this is not relevant to your question.
There can be interactions as to the prefered settings between VTA and cartridge loadings. In general low output MC cartriges specify a low impedance loading. You may prefer the sound at a higher impedance which generally gives more air but is less focused in the bass. If your sound is bright at the lower impedance loading you should definitely try to adjust the VTA by lowering the rear of the arm until the sound is "focused". If you go to far the bass will become "wooly". Then go back and raise the impedance setting until you get the sound you like best.
This takes a lot of patience, but the results are rewarding.
You can optimize MM cartridges by changing the capicatance, but this is not relevant to your question.
There can be interactions as to the prefered settings between VTA and cartridge loadings. In general low output MC cartriges specify a low impedance loading. You may prefer the sound at a higher impedance which generally gives more air but is less focused in the bass. If your sound is bright at the lower impedance loading you should definitely try to adjust the VTA by lowering the rear of the arm until the sound is "focused". If you go to far the bass will become "wooly". Then go back and raise the impedance setting until you get the sound you like best.
This takes a lot of patience, but the results are rewarding.