If shrillness and bass are a problem then indeed, you might try a ribbon or an omni for M.
First, you will need to have a proper matrix to "convert" the MS. It can be a hardware, or software ones. For the ribbon my recommendation would be Stellar RM3 (or ACM3), which is a Chinese copy of Royer R121. Normally, for this application I'd use a long ribbon (2") for its more limited pattern in the vertical plane, however, even though those have a medium-long ribbon, because of their long body and hardware obstacles the acoustical properties are closer to the long ribbons.
Another couple ribbons would be Apex205 or 210, however they have lower output, so you will need more clean gain from your pre. Also, their HF response is not as extended.
Hi Marik,
Well, the process of "decoding" is to much for me to understand without any "hands on" help here to walk me through it and I won't ask you to explain because you are not running a "recording school" just for me (-:
I was thinking anyway, that even though I plan to follow your suggestion of experimenting more with my NT1A's and Pulsars, I just have a feeling without actual experience, and after reading all that you wrote--- I have a feeling that in the end, what I am going to like best is two fig 8 ribbons in Blumlein config (I'm assuming doesn't need "decoding"--?) If I decide to get a little better mic than the Steller RM3, can you suggest anything else. I was looking online in the 6-700$ range at Byerdynamic 130, AT 4081, Groove tubes Velo 8, Sonotronic Sigma. -----Read the Groove tube has a 2.10" ribbon, didn't find ribbon length in specs for other mics. Back to budget mics, what about the Cascade X-15 stereo mic or Cascade DR 2S? That could really simplify things. Could get mods done I guess on any of the chinese ribbons. Once modded, think there would be any significant difference between them and the mid- price mics I mentioned?
To put it into easy terms, the "true" omnies are those, which are built around one sided pressure capsule. The SP LSD2 uses a two-sided capsule, AKA Braunmuhl--Weber design, where the omni pattern achieved by electrical summing of two cardioid patterns.
OK no LSD2 for me.
I never had a chance to try the MK012 omni capsule, so Michael Joly could be much more informative here. Generally, I prefer smaller omni diaphragm for their superior HF pattern, such as AKG CK2, CK62, SP C4, and esp. some measurement capsules, such as B&K4133 and Gefell MK221, which are probably the very best omni capsules for sound recording ever made (and price reflects it!

). Very small diaphragm mic such as Naiant and some measurement mics can be superb, but potentially might have some noise problems with distant miking, so check that, first, and Mshilarious would be the right person to ask.
Best, M