try a -6db/oct LPF across the Pitch patch for your portamento.
it gives a glide portamento rather than 'rate' portamento.
? works in synthedit. try different cutoffs, but i seem to remember
that cutoff =0 gives best result (? need to check, i had a list of
different cutoff levels, this may be wrong)
hey i see you've mastered Ctrlr ! ;-)
if anyone has a ronald D-110 kicking around, you might like to
give this Tone editor a whirl - it unlocks it quite a bit! first
working standalone version, just Tone Edit for now, Patch Edit
is in the pipeline, and maybe editing on all parts (soz for more
offtopic but you'll like this if you have D-110/10 and maybe mt32,
D-20, and maybe even D-5)
Ctrlr D-110 rev034i (alpha/standalone) zip
https://app.box.com/s/5jpixv96pmvsflooxsi49w69jl1iv4tr