I have no experience with modern Grado cartridges. However, I do own a Grado TLZ, which was one of their early efforts at making a low output cartridge. (Incidentally, I don't think the Grados are classic moving iron types; I think they are "induced magnet" types, altho that is a distinction without much difference.)
The TLZ was a great cartridge in its day. On the other hand, I also don't think that all high output cartridges are inferior to all low output ones. You have to take this on a case by case basis. I have several MM cartridges that compete with any high dollar LOMC cartridge. Bottom line: you would have to try both versions of the Grado Master and make up your own mind. My opinion: given the rest of your system, you would probably be just as well off to go for the less expensive option, which I guess means the high output version of the Master. What Photon did, buying two new phono stages to try to make his low output cartridge sound OK, is nothing short of heroic, and expensive.
The TLZ was a great cartridge in its day. On the other hand, I also don't think that all high output cartridges are inferior to all low output ones. You have to take this on a case by case basis. I have several MM cartridges that compete with any high dollar LOMC cartridge. Bottom line: you would have to try both versions of the Grado Master and make up your own mind. My opinion: given the rest of your system, you would probably be just as well off to go for the less expensive option, which I guess means the high output version of the Master. What Photon did, buying two new phono stages to try to make his low output cartridge sound OK, is nothing short of heroic, and expensive.