At first glance your existing McIntosh phono can do it all it seems.
For my first MC cartridge, I chose low output, because the whole idea of MC is to get refined movement/results from smaller/lighter parts.
AT33PTG/II, wide separation, tight channel balance, excellent sound IMO.
I go thru SUT to MM Phono in my tube preamp, you would just go to your existing MP100 and use it's MC internal SUT.
research the relationship of cartridge signal strength and cartridge coil impedance before and after signal boost, some are difficult combos. my .3mv and 10 ohm coil impedance is a fairly easy combination.