My family has three Devuan PCs and will get a fourth rebuilt.  I also have four Debian virtual private servers (VPS) which unfortunately run in something such as OpenVZ with systemd so didn't work to convert to SysVInit and still be able to reboot properly (did work for daemons while they were up)... bot those VPS are mostly off-topic; just saying I use Debian for some serious uses since maybe 1999 when it was still how Devuan is now, such as for workstations for computer programming/science (CS) and servers.

I have a set of configuration files I use for family PCs such as /etc/pam.d/common-auth, /etc/sudoers, /etc/default stuff, /etc/passwd, /etc/group, some /etc/apt*, /etc/inittab, /etc/inetd.conf, /etc/nanorc, /etc/screenrc, /etc/hosts template, /etc/resolv.conf, /etc/dhcp/dhclient-enter-hooks.d, /etc/aliases, /etc/rc.local* & /etc/profile.d files (my own environment.sh, functions.sh though were for bash), /var/spool/cron/crontabs, /usr/local/{bin|lib}, /etc/X11, etc.  I was pretty disappointed our 101-key IBM model M keyboards were undetected: you assumed 104-key/Windows so I needed /etc/default/keyboard, but I also have /etc/default/grub for improvements including reasonable/non-hurried boot time.

Are there any other configuration files you'd suggest?  I know some are in /var, which leads to something else.

I've been trying to use AMD's OpenCL on these PCs.  Often amdgpu-install works once on a PC but if the driver doesn't work so you have to uninstall & reinstall older, it no longer installs or sometimes might then doesn't work--network problem?  Might take some tens minutes or hours or just another day/week until any version installs again.  What I found is rsyncing /*bin, /etc (after backup like fstab, files containing hostname), /lib*, /opt, /srv, /usr, /var from another Devuan workstation/server fixes this and immediately makes OpenCL installed and working.  Is there a 'right' way to do this, like I know some configuration is also in /var or maybe some machine-specific files are installed elsewhere?  It'd also be a way one might quickly copy a Devuan install from an old to new PC without having to do an entire new installation.

Two the workstations--now more servers--I do this with are identical hardware except slightly different multi-function hubs (media dashboards for memory card readers, USB, audio, eSATA, molex power, etc.) though I was careful to not rsync /boot (despite they don't boot UEFI) or various specific/system stuff (/dev, /proc, /run, /sys, /tmp).  I'd guess anything different these two have is in /lib/modules and part of the main kernel packages anyway: I didn't install any additional firmware (well, likely main package, but didn't choose individual firmware packages) just some might get loaded (happens somewhere else?) in each but not the other.

Suppose those two are exactly the same, or if two have slightly different CPU, system-/logic-/main-/mother-board or peripherals, if you have preset/template configuration but want to save time by rsyncing, what's the right way to do this: stuff to omit or add or edit or look out for?  In /etc I just did 'grep -ir hostname *' for the hostname and it was quick, easy to fix, but configuration elsewhere (/var?) is another matter (might take hours to grep)... if you try this, however make sure to backup /etc/fstab and all /etc/* containing hostname and restore before any rebooting.  If you don't, the reboot process will halt, and you have to remount '/' rw and restore fstab, and you may have hostname/network issues.  No big deal but on one of several occasions I made this mistake, which if someone is new to this process might feel a bit intimidating (for an old UNIX user it was all kind of obvious).

When the installation CD/DVD is relatively small but we download some GB other packages, and instead of editing all configuration by hand on each new installation, I prefer presets/template for those, and in the case of something such as OpenCL no longer completing installation, then I find cloning with rsync to be easiest instead of trying for days and not being able to number-crunch for Berkeley Open Infrastructure for Network Computing (BOINC) for science until later.

On Devuan 5 (or when stable, newer) can one install OpenCL/AMDGPU-PRO, and how?  ROCm didn't work for me in the past, but might be AMDGPU-PRO's basis now, which lately works fine, and one can install only its OpenCL part... or is there a better way?  All I found on this topic was old/outdated material for older Devuan and much older Debian.