****I was really angling to use the high outputs,****
Why do you feel that the high output setting would be better? The opposite is usually the case since you are then using fewer gain stages (less is more). If you don't need the extra gain that is a good thing. One of the reasons that I have gone back to MM cartridges from low output MC's is precisely that; my phono stage sounds considerably better in MM mode (lower gain). Rest easy.
Why do you feel that the high output setting would be better? The opposite is usually the case since you are then using fewer gain stages (less is more). If you don't need the extra gain that is a good thing. One of the reasons that I have gone back to MM cartridges from low output MC's is precisely that; my phono stage sounds considerably better in MM mode (lower gain). Rest easy.