your thoughts regarding those two tunings ?

pros an cons on each ?

I often get pushback for my opinions but here goes.
If you keep the strict 5ths, the relationship of the strings obviously is consistent and less confusing. I always look for efficiency. In my extensive chords explorations, I've yet to encounter a chord I couldn't easily reach in standard tuning. Extended chords, altered chords standard chords, they're all accessible in standard tuning.
Guitar players change tunings for finger reach and alternate voicings. With 10 fingers it can all be accomplished in standard tuning.
Through various cover tunes in all genres, and composing my own ideas, this has worked consistently
These are my experiences.
Steve A

Steve please keep giving insights your knowledge is appreciated.

High Bass 4th is easy to go back&forth with, just tune down&back w/ the 12th string. Never broken a string doin' it (and neither has Greg H.) Currently playing with 7+5...that evolution comes from DBR to DMR to "hey, if I take a DBR string set and put the 12th string on as the first string, tune the melody up a half-step and tune the bass 'as is' I have Deep Matched Reciprocal with the low range in the melody like DBR. (huh?)

I took 2 years and tried most of the popular tunings including classic and baritone melody on a 10 string and classic 6+6 and MR on a 12 string. When I heard about high bass 4th and what it offered, it seemed easy enough to try just by tuning down the 12th atring. I liked that it added the ability to grab a number of 2 handed chords with just the left hand. My one and only formal sit down Stick lesson w/Bob Culbertson started with Bob having me tune back to straight 5ths. I entertained the idea of adding a Keith or Scruggs banjo tuner with 2 tunable presets for the 12th string and discussed it with Emmett when he was building my bamboo Grand so I could have it both ways. In the end I just tuned it to a 4th and left it there after realizing that in practice 90% of the time it adds more than it detracts because most of the time you can reach both the old note and the newly reachable note. If tuning uniformity is paramount for you, your mileage may vary.

I think the answer depends on how often you use the high bass string. When playing in my band, I use it frequently because we have a bass player and we (mostly) try to avoid overlapping frequency ranges. When playing solo, I go back and forth depending on what I am playing. I would stick with Classic and shift to hi Bass 4th to change things up. I like the Classic tuning the best on the Grand Stick.

Jeremy

I must be missing something.
What is the benefit of tuning the last string down a step unless it's for TL's Elephant Talk?

Steve A

Pros: Some really nice 4-note chord voicings, requiring only one hand to execute. Especially nice are the 7#9 with the second bass string in the bass, and 13 with the lowest string in the bass. these voicings can not be achieved with only one hand with only 5ths.

Also, since the 10th and12 strings are an octave apart you can play major and minor triads off the 3rd bass string with a 5th on top, and using a triple stop with the index finger you can get a 5 note power chord off the 2nd bass string: Root-5-Octave-5-Double Octave.

Cons: Lack of conformity with other bass strings.

If you want to try this, try it. If you don't, don't... It requires no setup change to your instrument to give it a go.

I really need to make a video about this topic...

good one Steve, but I think Tony uses a half-step drop for his epic tritone double stop.

True story, I once met a guy who learned how to play it without changing the tuning... boy was he surprised when he found out how Tony did it...

Yep. It's all about having an upper register tritone inside your left-hand reach.
Close voiced extensions like 6th plus a 7th or 7th plus a #9th tone in the top end of a left-hand chord or arpeggio are handy when you can snag them with one hand.