I should have been more careful in my advice: chances are that you'll want a C-shaped shim rather than an O-shaped one. See part 04 on this Deda parts diagram as an example (part code HDDCRMS - DCR microspacer).

https://dedaelementi.com/media/catalog/product/attachment//d/c/dcr_headsets.pdf

Hopefully, a C-shim won't require much disassembly; make sure though that the dimensions of the shim match those of your headset.

Existing RD301d users, does your headset rubbing with the upper headtube when turning? Mine does. Plan to grind off the plastic cover spacer that's rubbing with the headtube. If it happened on yours how do you address it?

Maybe use a headset shim, something like this? https://shop.fullspeedahead.com/en/spacers/road-mtb/micro-spacer

In other words, no one was asking for sympathy, just regular human decency.

I assembled a calibration jig over the holidays, mostly using AliExpress parts and a few bits and bobs I had lying around. The design is based on various other designs that are floating around on the interwebs.



Frame:
2x 2020 aluminum extrusion 600mm (the length depends somewhat on the length of the scale and spoke; the image shows a ~280mm spoke)
2x 2020N aluminum extrusion 200mm (2020N (as opposed to regular 2020) has one solid side wall; I chose it for extra rigidity but plain 2020 probably would have worked as well)
4x corner brackets with T-nuts and screws

Center section, from left to right:
M8 threaded rod (I bought a 1m rod and chopped it into pieces)
M8 nut (I used a flanged nut but a non-flanged one should work just fine)
thrust bearing 8mm inner diameter, 22mm outer diameter
M8 cap nut
nipple + spoke
M8 'I-type' clevis end - for J-hook spokes; for straight-pull spokes you'd use a second cap nut
M8 rod
2x M8 clevis end (aka yoke end or Y-knuckle on AliExpress; attaches to the scale)
crane scale in the 150 to 200kg range; I chose the most compact model I was able to find
M8 rod
M8 nut (thumb nut in this case but a regular nut will do just fine)

Fabrication:
drill 2020N extrusions for M8 rod
drill cap nut so that a spoke nipple can fit through
grind short groove into the 'I-type' clevis end so that the spoke head can be slotted into it (as mentioned, for straight-pull spokes, use a second cap nut)
I also had to grind the 'Y-type' clevis ends slightly so that they fit into the scale without interference

Note: under tension, the J-hook spoke head will deform - in my experience, it'll remain in its groove securely but count on one sacrificial spoke for calibration. (I'm guessing straight-pull spokes don't have that problem.)

Sources:
2020(N) extrusions and brackets - Zhuhai store (cheap but very slow shipping) https://www.aliexpress.com/store/1100992109
thrust bearing - https://www.aliexpress.us/item/3256806942964649.html
'I-type' clevis end (M8 version) - https://www.aliexpress.us/item/2251832818258210.html
'Y-type' clevis end (M8 version) - https://www.aliexpress.us/item/2255799845781219.html
crane scale (150kg version) - https://www.aliexpress.us/item/3256806675357153.html

Everything else I got locally.

Calibration:
You'll need two wrenches to put tension on the spoke, one to hold fast the cap nut and another to turn the left-most (flanged) nut. (Adding tension is a little fiddly but using a closed-end wrench for the flanged nut (or even a ratcheting wrench if you have one) makes things easier.)

Tension your spoke to a specific value (e.g. 70kgf), then check the reading on your tension meter and write it down. Repeat these steps for e.g. 80/90/100/110/120/130kgf and create yourself a tidy little table with kgf + tension meter readings. Check everything a few times.

Disclaimer: if you kill yourself using this jig, don't blame me. If you kill yourself using a wheel built with this jig, don't blame me.

Cost:
Roughly USD70 - I had a few pieces already so that helped.

To be fair, they do mention the screw in the manual:

Can anyone recommend a resource for walking through a build for these Chinese frames?

Youtube is where I would go - here is a two-part series specific to the Hygge model by Henry Chung (who also posts on here I believe).
Part 1 - https://www.youtube.com/watch?v=qz9O7tMQVe4
Part 2 - https://www.youtube.com/watch?v=58-htKDpXQ0

Maybe it's helpful to watch a few general build videos in addition to the above, starting with everyone's favorite Youtuber*, Trace Velo.
£1000 AliExpress Carbon road bike build - https://www.youtube.com/watch?v=FRVsX2WEkqg

Jourdain Coleman has several build series that provide additional details.
See the four 'Bike Build' playlists - https://www.youtube.com/@JourdainColeman/playlists (I'd focus on the 'build process' videos within the respective playlists, the rest aren't that relevant to the assembly of the various bikes)

* Sorry, couldn't find a build video by everyone's other favorite Youtuber, Patrick Lino.

Is there a good primer on this?  I know the big coupons run out.  When does everything go live - is there a time of day to get this going to capture the best deals?  I'd like to grab a groupset and want to hit it properly and not feel like I'm trying to get Taylor Swift tickets.

Going by previous years, the sale will start 8 a.m. GMT (midnight PDT); stores will advertise 11.11 prices a few days in advance, however. Expect things to be quirky - for example, when trying to apply a coupon, the site may tell you that it doesn't recognize the coupon... only for the coupon to work on final check-out anyway. One way to deal with the chaos is to create yourself a shopping list - know what you want to buy from which store at what price and only go through with it if you see real savings.