Sooooo... the test with the Formulary recipe didn't work out. I'm assuming (if my measurements and temperatures were correct) that replacing thin boiling starch with Clear-Jel is the culprit.
It came out of the pan gooey and never fully jelled even after drying it in the dehydrator for 48 hours at 150F.
However, I went back to my previous test recipe that I'd been working with (corn syrup, sugar, corn starch, modified corn starch, flavoring and coloring) and adjusted the starch ratios a smidge.
3 parts corn starch to 1 part modified corn starch seems to be close to the magic ratio.
And now I have a moderately successful batch on my hands. The batch pulled slightly from the sides of the pan upon cooling and after spending 48 hours in the dehydrator at 150F, it slid out of the pan easily.
Was able to clean off the excess corn starch with a misting of water, slice it into clean squares and then roll it in sugar for another few days of room temp drying.
As is, it's chewy but not overly gummy. No stretchy strings and a clean, firm bite. I'm thinking the sugar coating needs a little citric acid and the jellies themselves could probably use a pinch of salt.
A few observations:
1. Too much corn starch and your product is crumbly and cloudy, too much modified corn starch and you have candy flavored canned pie filling.
2. As the mixture heats up to the 175F - 200F range, the corn starch jells and becomes very cloudy and viscous. As it rises to boiling and ultimately 226F, the mixture gets more translucent, thinner and syrupy.
3. Monitoring the cook temp of starchy goo is aggravating. The temperature can vary wildly from the bottom of the pan to the top of mix. I had one instance where there was a 10F difference in the same pan.
I'll get a few more batches done before I post any more photos.