Today's iteration (attached "zipper 3") closes the gaps, except for two (at the 1/3 and 2/3 point), and the remaining gaps are much less pronounced, so the zipper is much more robust. The gaps obviously should not be there at all (tinkercad shows the two junctions slightly overlapped), so I'll do another iteration on Sept. 4 setting more overlap, which should (hopefully) clean that up.
Note that the zippers are about 160mm long with this design; the 85044A expects the zippers to be about 150mm long, just cut the excess off.
It turns out that neither of the export file options (.stl or .zip) from tinkercad preserve object groups (I'm really curious as to why autodesk would publish this tool (tinkercad) with such severe shortcomings - certainly it isn't an incentive for me to spend $$$ on a paid product from them), so it's not feasible to import the STL file into tinkercad and edit the design to make further changes, however, I'm going to continue iterating until the gap issue is resolved, so that if someone comes across this post in the future, they can print the zipper parts directly.
More in a week...
