> sample accurate MIDI
MIDI timing accuracy depends on the receiving hardware.
I'd try to understand first what causes the timing to be sloppy in the first place... There's no point in having sample accurate MIDI if there's jitter introduced by the software running on the receiving end. Which is probably going to be the case for any old vintage synth (say the Matrix 1000).
Similarly, the Shruthi has, by design, up to 1ms of delay between the time the last clock transition of the last byte of the MIDI message; and the moment the note starts.