You're spot on wisely_foolish <typing now>. Actually, what I never got to in the above rambling, was the "cache document" command actually includes the purge step. So, you're right on about the use of cache.
I've added a studio microphone to this set-up and learned a few things:
(I'm not suggesting folks go out and buy an expensive mic like I talk about below, but I thought I'd share the lessons learned from the exercise):
1. Added a studio Sure microphone to a new profile - yes, the app balked saying it was unsupported but I clicked through anyway
2. I ran the mic through a small mixing board, where I turned down all the highs (tone quality: highs = 0, mid-range = 3, low end = 5)
3. used a 1/4 - 1/8" adapter to plug into the iMac line-in plug
1. Once you have a microphone that you can clip off/control the high tonal range & fine tune the gain, you can alleviate some of the extraneous noise, thus reducing some of the words that seem to appear for no reason in dictation mode. Crappy mics produce "tinny" sound that translates into background noise and thus bogus words. Lesson: better maximize the quality of sound input the mic generates - the app is not capable of doing so.
2. The two points Wisely_foolish noted above are spot on: save all your corrections for the end. After two corrections I would issue a "cache document" command to realign the documents contents with the internal data (sound data, etc). If you must do any by hand , I'd cache immediately after.
Also, save all edits until you're done with your session. After you're done dictating, go back to make corrections. I issued a "save this document" after each figuring each edit would be my last before the app crashed. Having said this, it seems, for now at least, this app is only good for long dictation where the assumption is that you will only make one pass at dictating and hope the app is 80% or better with accuracy. Once you start editing, the first time you start running into problems editing (i.e. inaccurate replacements, lines disappearing, etc) stop, save the doc and resume editing by hand. You will lose more time fighting with the app than you would have editing by hand and thus have negated the benefit of using the app in the first place.
3. Use "sleep mode" often. The more I put myself in sleep mode, the less chance of background noise producing garbage text.
4. Refrain from issuing commands in dictation mode. I had more success with the "command mode" <issue command> "dictation mode" use case"
Golden rule: Only use this app if you're going to do long dictation and you go into it with the assumption that the app will only help you with the initial "thought dump". This is the only spot in the workflow where you will realize a benefit. if you rely on the app to perform edits, the time you will lose will negate any benefit you realized on the front end. Using the app to dictate short passages will only cost you more time than if you typed it out initially.
As for using the app to "boss the computer around" I wouldn't trust it. I can only imagine the nightmare scenarios possible when DD decides to interject it's own thoughts into a email I'm sending.