[mythtv-users] Advice on v31 installation?

[f-myth-users at media.mit.edu]

Hi.  I'm looking for some advice on installing v31.  I'll be doing so
under Ubuntu 20.04.

I'm currently running a truly ancient version.  I'll be installing on
an entirely separate machine and running both in parallel while I figure
out my v31 installation.  To start with, I'm just going to set up a new
database, at least for testing; once I get everything working, I -might-
dump the new, test DB and try to migrate the old DB, but it's going to
be quite involved and I'm on a bit of a schedule before Comcast drops
support for my equally-ancient cable boxes, so I'll get the test system
running first and ask any questions about migration later.

(a) I don't want to interfere with the ancient myth's lineups (using DD)
in any way while setting up the new machine's lineups (presumably using
XMLTV).  The two lineups will be -very- different because the two myths
will receive via very different hardware and have access to different
channels.  I see that SD supports up to four lineups, but can I rely on
a new installation using a new lineup and not bashing the old one?  How
are they differentiated?  The SD web interface makes it look like I have
to pick a unique nearby zipcode (pretty sure that's what I did years
ago); is that the way?  [If I can't be sure, I can pay for a brand-new
account (a couple months or a year) to guarantee they stay separate,
although I just paid for a new year on the old one and I assume that
money's sunk.  I'd rather use the existing SD acct, but only if safe.]

(b) Is it wise to use the Mythbuntu Control Panel to do the initial
setup, or should I install everything "by hand" without installing MCP?

(c) I've seen rumblings on the list re MySQL compatibility.  Should I
preinstall MariaDB instead, and if I do, will MCP install MySQL anyway
or will it see that the dependency is satisfied if I install MariaDB
first?  (And I assume if it installs MySQL I can just remove that and
leave/reinstall MariaDB, if MariaDB is currently the recommended DB?)

(d) Should I prefer the JSON or the SQLite versions of the XMLTV grabber?
If I use MCP, will it enforce a choice?  Do I still have to worry about
configuring either grabber differently so it doesn't try to use gigs of
RAM?  (I have a vague feeling that might have been solved between the
version of 31 prepackaged w/20.04 and the current version, but I haven't
checked when that may or may not have been fixed; the version the non-PPA
20.04 ships is claimed to be 2:31.0+fixes.20200323.9579662cdc-0ubuntu1.)

(e) I'll be using a Ceton 6ETH (or a couple of them) to capture.
I've stashed away a few sets of advice on this over the years, and have
already paired one with a CableCard and ensured that works.  So far,
it/they will be sharing my network, although I hope to add Ethernet
ports to the production backend eventually to reduce packet contention.
I also have some 120mm fans for cooling it/them.  Any other gotchas I
should be aware of?

(f) And in general---any other gotchas that spring to mind or things I
should be asking about?

Thanks!