hoping to get that tick-tock bass sound of the old C&W records, which sometimes was achieved by a guitar playing along with an upright bass.
I believe the tic tac was usually done on a Fender VI Bass.
Cited here:
How to get the tic-tac bass sound - The Record Shop Nashville
When that sort of arrangement was established in Nashville pop-country recording practice, it was all Danelectro UB2, until other Dano models and competition by other companies (the Gibson EB-6, the Fender VI) appeared.
The article insists upon calling the instrument a baritone, and cites its tuning as being B to B accordingly. That may be the standard now, but it wasn't then.*
An important thing to know about the "tic tac" arrangement is that it was done with the upright and the VI-bass playing (more or less) the same, previously agreed upon line in unison, and that is to be intended in the proper sense of the word: mostly the same notes,
mostly in the same octave - which the VI tuning i.e. low E to E allowed.
IMO using an 8-string is a move in the wrong direction if nailing the Patsy Cline rhythm section, as opposed to reggae bass+guitar octave riffing, is the goal.
[Well, that, unless you try something wacky, such as putting on a unison mixed set made of the darkest and the brightest strings you can put your hands on: something like Rotosound black nylons + a
stainless steel (light) set of your choice. And maybe learning to pluck the pair with index + thumb, with the one that plucks the bright string armed with a fingerpick.]
* The UB2 was simply Danelectro's take on the "electric bass guitar" concept, at a time ('56) when only 4 models or so of the instrument existed at all; it was thought of and called a "six-string bass", because the modern instrument with that name (long scale, low B tuning, wide spacing) was yet to appear. As for the "baritone guitar", it didn't exist either: the whole idea of the baritone guitar (bar isolated, bespoke one-offs) was conceived in the '70's with old Dano and Fender 6-string basses being used strictly as lead instruments (as they often had been since the previous decade), and ultimately retuned up a 4th or a 5th.