Well then, having been initially convinced that a heated ultrasonic was 'the way to go' for steeping, and having used it for months (each blend getting 4, 30minute sessions with heat around 150 degrees), but finding that MANY juices still need more steeping to finally 'settle in' - we decided to try the "4 hours @ 150" that buffaloguy was kind enough to discover, painstakingly test, and share.
We've just completed almost 7,000ml of various juices (largest size of bottle was 60 mls, so that's a LOT of different flavor combinations - including some tobaccos). And you know what? ALL OF THEM THAT WE'VE MADE BEFORE (many that had to have a couple of weeks after the 2 hours in the ultrasonic) ARE PERFECTLY STEEPED.
We used our food dehydrator set to 150 degrees, and left them in a minimum of 4 1/2 hours, uncapping/burping, recapping, and shaking thoroughly every hour or so. We left them in longer than 4 hours to ensure they actually got 4 hours at the full 150. (EDIT: with a few of them, we weren't able to give up our 'ultrasonic addiction', so a few got 2 hours at 150 in the ultrasonic and the remaining 2 hours in the dehydrator). We're putting that noisy contraption on the back shelf (unless we need to use it 'for heat' over the summer when our dehydrator is busy with garden produce or making herbal concoctions).
buffaloguy, we seriously appreciate all the time & effort you've devoted to testing & posting. This kind of data is exactly what the DIY forum is sorely lacking in, and it's the kind of data that makes ALL the difference to successful, exceptional juices. KUDOS & THANK YOU!
And RobertNC, thank you, TOO (very very much!). We've been sharing this information when we get the time and some folks have been grasping it and using it successfully (well, actually 'not using it' successfully

)
Hopefully we can all start copy/pasting this info to the newbies, and we can 'turn the tide' away from all the misinformation, and get folks back to understanding the difference between "oft repeated advice based on nothing but oft repeated advice", and actual testing & validation!