Ahh, I see it now... it wasn't there for me yesterday when I replied.
and.... wow. that is amazing to see how you simplified the end result (in it's unworkable, post-mesh-conversion form) down to something so minimalistic and used the pattern to great effect... I've used the pattern, but not nearly that effectively.
That will be a big help going forward as well as making the main shape solid and then shelling it.... I've been sketching out the part one dimention at a time, extruding the walls manually... horribly inefficient, in hindsight. Which is why I was avoiding re-creating this thing from scratch to make it workable.... my way would have taken forever and been absolutely miserable compared to your much faster, much more elegant approach.
One question so far...How can I find the variable name of a dimention in order to reference it like you did with the Dx/2? that will be very helpful as well.
I've asked questions on forums plenty of times over the years, for various tools/apps/etc.... but I've never gotten the kind of detailed, step-by-step walkthrough you just provided.... I'm blown away.
Thank you very much for taking the time to show me "the right way" (or better, anyway) to do all these little aspects of the workflow. this is going to help me tremendously and I sincerely appreciate your time and effort to help me out.