To be honest, I'd never heard of the ninety degree thing.  I just rotate it enough for the barrel to be next to the frame so I can tell how much to add to the arbor.

  All is not Roses 

I desperately wanted these guns for the lower/wider hammer.  Alas, not a good idea.  Muscle memory is killer.  I just can't operate the guns with the lower hammer.  They gotta go.  The "Thunderball" Grip also doesn't fit my hands.  They gotta go.  Oopsies, I bought the wrong version of the guns.  EMF has the same gun with Plow Handles and upright Hammers.  Live and learn.

Mechanically, the guns are really good.  The only real problem has been the fit of the Barrel Bushing which had to be driven out and dressed to fit and turn properly.  The Base pin was also a real groan to get out.  The cross bolt is heavily sprung as is the Ejector.  I scratched the bottom flat of the barrel (girrrrrrrrrr).  And I did whack the last 3/32 off the base pin to eliminate the stoopid safety portion.  Gonna be real fun guns when I finally get to play wid 'em you betcha.

  Oh Bother 

How did Pietta sneak into this conversation??  We were discussing Uberti wern't we??  Just as a point, over the last 15 or so years, I haven't found enough error in the Barrel to Arbor fit in Pietta to be concerned about.

Regarding the 90 degree barrel twist, only enough offset is required to gauge the amount of overlap (should be zero).  The problem lies with the poor matchup between the bore in the Barrel Lug and the Arbor.  Mostly, out of the box, the barrel has had to be "driven" onto the arbor and the "driven" off to disassemble.  Just looking for a "witness mark" in the bottom of the hole will only confirm the whole assembly doesn't fit properly.

Now, to be honest. I can't speak for Uberti guns made over the last 4 or so years as I have taken down my shingle.  However, if Uberti couldn't be bothered to fix the problem over the last two or three DECADES I would not expect it to be corrected now.

I measured and weighed an original Colt Pocket Navy in .38 CF and the Uberti Pocket Navy .380 ACP, both have round 3,5" barrels.
99,9% identical measurements incl. the weight.
Regarding sales in Germany of the little sucker since the importer received the first shipment in early 2019: three specimens only!
As a 5-shooter it is not legal as a main match pistol in CAS matches over here as opposed to the SASS rules.
On the other hand we have practically no side matches for pocket pistols.
Long Johns Wolf

My pair of 1861 RM Conversions in .38 Long Colt cal.
They are my main match pistols since 2018.
The one with the silverish grip frame is a 2nd gen Colt, the other a 4-screw frame Uberti.
Long Johns Wolf