dman, I am happy to learn that I was incorrect in thinking you are going to drive an inexpensive Focal bookshelf speaker with the Luxman 595. I apologize for my error. I have always been a fan of the better Focal speakers, so I am sure you will have a lovely analog system once you decide upon a cartridge to go with the Technics TT/tonearm.
In deciding about the adequacy of your system gain in order to determine what cartridge output is suitable, you need to know the following: (1) The output of the cartridge in millivolts (mV) and the criterion for determining the output voltage. There are two standards; in the older case the signal V is measured at a stylus velocity of 3.54cm/sec and in the current era, the signal V is measured at 5cm/sec. In both cases, the measurement is made at a frequency of 1kHz. (2) The gain of the phono stage. I searched the internet to find the MM phono gain for your 595, and all I found was that bit about "input sensitivity", 2.5mV. One really needs to know the gain in db. Someone here, I think, mentioned "48 or 50db" for the MM section. If it’s really 50db, then you have a lot of freedom to choose cartridges with output as low as 2mV. The typical MM stage has 39 to 42db gain. For comparison, 40db means the signal voltage is amplified by 100X, whereas 50db means the signal voltage is amplified by 300X. An MM stage with 40db gain will output 0.5V from a cartridge with the typical output of 5mV. 50db gain gives you an 0.6V phono stage output from a cartridge with only 2mV to drive that stage. (2mV*300 = 600mV = 0.6V). I don’t know the MC gain of the Luxman, but it sounds like you have a wide choice of cartridges from which to use owing to its flexibility. If you are obsessed with moving mass, MI type cartridges have lower moving mass than MC types.
In addition, (3) the linestage of the Luxman will add more gain to the signal that has to drive the amplifier. And (4) you will need to know the input sensitivity of the amplifier section. That is defined as the signal voltage needed to drive it to full output. The typical modern amplifier exhibits an input sensitivity of between 0.8V and 2V. (5) Then speaker impedance and efficiency enter the picture. All 5 of these factors plus room size and acoustics finally determine how happy you will be, SPL-wise.
