There aren't a lot of cartridge manufactures that sell different output levels of the same cart, are you willing to change brands?
Um, there are several who do exactly that. Benz and ZYX come instantly to mind and a little research would turn up others.
I've A/B'd the low and high output versions of several ZYX models. In my system the low output version was invariably superior, so much so that I advised the US importer not to bother stocking the HO output versions of any of the expensive models.
However, the qualification "in my system" was critical. I'm fortunate enough to own a very fine phono stage, capable of amplifying even very low level signals with minimal noise or distortion and with exceptional transparency. As Stanwal and Viridian noted, the challenge of cleanly amplifying very low voltage signals is not easily (or cheaply) met. Many phono stages that have sufficient gain for a LOMC lack the transparency, speed, clarity or other capabilities necessary to fully reproduce everything the cartridge is capable of. In such a case, one's monies might be better spent upgrading the phono stage before investing in a LOMC.
The EF1 is a reasonable phono stage. It has enough gain for low (but not very low) output MCs, down to around 1.0mv or so but not .25mv and possibly not .5mv. The specs don't indicate whether the EF1 has adjustable input impedance. This is vital for optimizing any LOMC. Ask c-j about this before investing in an expensive LO cartridge. (If they tell you it's unnecessary run, don't walk...)