Maybe you look at the wrong direction.
I know this harmonic organic completeness of your 3012 and that was the reason which directs me to buy my SAEC (as you probably know, there are only these 2 brands that utilise the knife-edge bearings). When I have the 3012 I've matched it with a Decca in order to elevate it's dark personality. But I would never advise you for this once the Decca's demands upon everything in the system, the LPs condition and every day use are a nightmere.
If you dare to experiment with a couple of headshells, then please give a chance to a used VDH Colibri LW gold before you swap your 3012. You really can't imagine what you're missing. Conqueror is not better than a Triplanar (but the cheap Clearaudio Satisfy it really is!) and don't bother for the ARO (just because you trust the firm). I have both in the past and the ARO is a very vicious monster about cartridge match and even armboard & overall TT philosophy. It's not good on handling either, while has an average performance. Some of us we have change over 20 cartridges till we find what works in our set-up. Do you really trust the DL103, RS30 as the upper limit to your quest?
About matching with 3012, I'm not expecting any surprises, but please do not stuck with this perforated heashell. Ask our Raul about the proper one, change the internal wiring and examine the condition of the (unfortunatelly plastic) knife-edge bearing.
My first recommendation to you, if you didn't have a budged limit, it would be the SAEC WE-506/VDH Condor. But the Condor never appears in the used market and the WE-506 (that is the 12" model) is priced from $2850. The 9.5" that I have (WE-308SX) $950 w/o headshell is very different sounding from your 3012. Not a sight of darkness or dullness, but at the opposite side of been at the edge of brilliance. Now imagine that this was not enough for me and I've hardwired from headshell collar till the step-up with VDH MCS 1000M (silver). I've changed the headshell with the Zonotone Z-10 'cause on this tonearm you must swing the cartridge to the headshell in order to align for Baerwald. I'm perfectly happy pairing it with my Colibri XPP & my Thorens TD124 II.