TBH I do not have any experiences with hardwares-ynths so far.. I had a D50 back then, but sold it about 7 or 8 years ago.
Sorry, if this sounds stupid, but i have some modules for Reaktor, that sound pretty organic. The oscs of them also all have their resolution reduced to 12 bit and this helps a lot.
Also I do not know, how hardware-synths handle frequencies above 20kHz? Maybe try recording at 96kHz to shift the aliasing into a non-audible region. IMHO oversampling/aliasing can greatly alter the top end and destroy the “warm” feel.
I bet @synthesizerwriter could say way more to this oversampling/aliasing-topic?