In case folks haven't seen it, Ellis' Print Tuning Guide is an excellent source of printer calibration and tuning information.
I noticed that there were some Pi4 1GB boards available from various sources, and I checked my two operating Vorons for memory usage. The highest current usage is 0.22GB. The Voron folks say 0.5GB is enough memory for a Voron running Klipper, so the 1GB Pi4 is more than enough and at $35 a good buy (the Pi3B+ costs the same, I'd rather have the 4B-1G). I have been using the Pi4 2GB units but those have more memory than needed for most applications and cost more. Octoprint also runs in the 0.5GB Pi Zero 2 W so the Pi4 1GB is adequate there too. Nice to have these options again.
The Pi Zero only has one USB which is generally enough for Octoprint usage but for a Voron more USB ports may be needed so the four ports on a Pi3 or Pi4 make things easier. On my VZero.2 I'm using 3 USB ports - one for the controller, one for the toolhead board, and one for the display board. The Trident uses a DSI display so only using one USB there, but other USB ports may be desired for camera or accelerometer PC boards.
I'm glad to see that availability is getting better.
Currently, i have two Raspberry Pi CM4s in Pi4B adapter boards, A BTT CB1 in a Pi4B adapter board, and a Orange Pi4 LTS.
I've been using the OrangePi 4lts as a desktop PC. It actually makes a pretty good one for word processing, surfing the net. The CM4s and the BTT CB1 are in a drawer, as backups.
Which CM4 adapters have you used? I have a few CM4's that I snagged during the shortage that I may want some for. Unfortunately it raises the cost to buy an expensive adapter for a not-cheap CM4, but it does give emmc and might as well use them. I have one Manta controller for a printer project that hasn't been put together yet. The Pi4 1GB I ordered this morning has already shipped. I always kept a Pi or two on the shelf but since this shortage I've wanted to deepen the inventory. I was looking the other day and there are 16 Pi's in service or configured as spares here. They sneak into many projects over the years... Two GPS NTP servers are Pi's, one is set up with a DAC and chrontab for our clock radio, one by the TV we use for streaming, three in printers, one for DNS service, one is in a clock - those $10 Pi Zero W's were inexpensive enough to put in lots of projects, now the least expensive Pi is $15 and the $4 - $6 Pi Picos are taking over the low end projects that don't need Linux.