A shame that this one came so close behind another alphabetic string puzzle, one executed more elegantly. Patrick's concept works, but it doesn't have as tidy of a feel, since there are many options for each string. ABCDE, for example, can be found in ALBRECHT DURER, BAREBACK RIDER … and ALPHABETIC ORDER!

Solid work, though, in coming up with a full set of themers that fit into crossword symmetry. Although each of the themers has other options, there's a nice FenG sHuI to how Patrick laid out the grid. There aren't dozens of options for each string, so there's undoubtedly a lot of juggling and sorting required to make symmetry work.
If your knee-JerK refLex was that it was too easy to come up with alternate themers, remember that a lot of the options would have been too long to work with. Seven shortish themers are hard enough.
Patrick did a nice job of building around his seven themers. Perfect to stack ABSCONDED and AFGHANI in adjacent rows, effectively making it like he only had to work around five themers.
I did notice a bit of NSF / CEN / MST stuff, but that was easily overlooked.
The only real blip in the craftsmanship is something I usually don't care about — added Ss. Some constructors say they hate plurals as inelegant, which mystifies me. If the words are in common usage, who cares if there are a bunch of plurals?
Well, I do, if they're the ilk of ILKS and USAGES — not commonly pluralized words. Toss in UKES (uke isn't as common as ukulele) and SKYS, and it felt like too much glue from one class of offender.
Big fan of two clues: MICE might "squeak by," indeed. And I sure hope my dentist "knows the drill"!
Difficult solve, which is what Will aims for on a Thursday — it took me forever to piece together the theme entries. I enjoy working hard for my a-ha moment, but only if the payoff is worth it. Knowing exactly what I should be doing from the start, but still having to struggle to complete the grid, wasn't that satisfying.