Well it took some experimentation - and an email to Garth at Chicken Systems - but I am now happily translating my entire EPS/ASR library into Kontakt format.
It's true I'll probably only use a small fraction of those instruments, but in addition to the ones I know I want there are some cool "old friends" I might not have otherwise thought of, and instead of having to do the translation on-the-spot I'll have access to all of it all the time.
The key was a couple of settings that I had forgotten about, so for anyone attempting this trick:
1) be sure to set the sample "type" properly in the Ensoniq Format Options - the default is "ASR" and if you use that for early EPS instruments you'll run into all sorts of loop problems.
2) if you want to convert the CC messages to key-switches you'll need to set that in the Ensoniq format page as well, and you need to check the option that combines the four presets into a single instrument.
Other than that you may want to set destination options to create the file hierarchy you prefer, but that was all that was required to get me on track.
And thanks Garth for answering my query so promptly!