I wrote a SID to MIDI conversion program which is far more advanced than the commonly known SID2MIDI program and it was quite difficult to get even the basics converted.
You can get it in my XSID repository at https://github.com/M3wP/XSID if you wanted to try it and see what its capable of.
I didn't even try to process the filter changes. I wouldn't even know how to automate the cutoff frequency and resonance controller changes, it would be nearly impossible to do. Its something that would have to be delicately managed by hand.
The pulse width changes are put in as custom controller values but they have no real effect, you have to look at them and change LFO and pitch envelopes to suit. Again, a totally manual process and one that has even less likely-hood of real success than trying to copy the filter changes.
I'd love to get a Gaia and try to do some better conversions but the problem with it is that you can't control the individual tone generators as easily as you can the SID voices. I looked into it and something like the MAudio Venom would potentially do a better job but again, it has its short-falls (and I'm a Roland fanatic).
No, the SID is quite astounding. I'm very much looking forward to having two and a more powerful machine to drive them.
I started writing a SID synth modelled after the Gaia (I called it the XVSID-01) that uses ReSID but using it on a PC is a bit dull. Hopefully it will be possible to connect a MIDI controller (for input) to the M65 and I'll write it on there, instead.