What cartridge to match with Audio Research PH-3

I am running a PH3 with an LS15 right now with an Audio Technica AT 150ML with 5.0 mV output. The PH3 does not come even close to overload. The LS15, of course, has the volume control attenuators on the input side of things, so it doesn't have an overload problem. If you are running single ended output on the LS15, the gain is only 6dB (a factor of two on voltage) and the relatively low gain helps. The key is the volume control position, which is dependent on the input sensitivity of the downstream power amp and speaker sensitivity (efficiency). With my ARC D115, the input sensitivity is very high (0.6V at clipping) and the volume for normal listening is at about 9 0'clock. With my other amp which clips at 1.7V, I listen at about 11 o'clock. In either case, the LS15 volume steps are not too coarse and the lowest volume setting is low enough for late night listening that is not too loud. My speakers are inefficient, however, (Magnepan 20.7s) and produce only 86dB at one watt. My experience is that, unless you are running super efficient speakers like horns, you should be OK.

i'd use medium out mc cartridge anywhere fr .6mV to 2mV.
the rest of parameters compliance, weight will depend on your tt/arm