On those Victor sides: they were using similar western electric equipment to Okeh/Columbia but handling it differently. They ended up having a very rich, warm bottom end response - I remember reading an article about this on the web somewhere but I can't remember where for the life of me. Perhaps they were trying to equalise their records in such a manner that would show off their Orthophonic victrolas!
This warmth would lead to a perceived lessening in high frequency response, whether there actually was one or not. I haven't compared a graph of high end response of a Victor and an Okeh from that period transferred raw, with no EQ (other than to correct the reproduction curve), but I would suspect the Okeh would have a slightly better top end response but not out of this world better. Also take into account that Victor surface of this era are quite a bit noisier than Okehs/Columbias, which in top shape, have some of the quietest surfaces you will ever hear on a shellac 78.
This gives the restorationist greater scope to boost the top end of an Okeh/Columbia disc to make it sound clearer - but of course there has to be something on the disc to boost. Have a listen to Paul Whiteman's "'Tain't So, Honey, 'Tain't So", there isn't a lot of top end in it to boost, but it ends up having a lovely warm sound. Perhaps they were trying to imitate Victor!
This way of working has some good effect on Victor discs - Steve Brown's stunning slap chorus on Dinah wouldn't hit you between the eyes in the same way on an Okeh, and his bowed part at the beginning of A Lane In Spain. I suspect these would not be anywhere near as strong on Okeh. As a point of comparison, have a listen to the McKenzie/Condon's
Chicagoans sides recorded for Okeh in late 1927: the string bass is a lot of click and not much bass, it's difficult to discern the actual notes Jim Lannigan is playing. The second session is a liFttle better than the first but it's still not very strong. The Louis Armstrong Okehs with string basses are stronger but then they're from a bit later on. Does anyone know if Okeh did any string bass recordings in New York in 1927, and if it comes through strongly?
Specifically on "Clementine", I think the medium band in a large hall theory is quite right. There's a particular resonance on that side that muddies everything up a bit, the second string bass note hits it right in the middle and resonates like you wouldn't believe. Mr. Davies managed to tame it a little bit, probably by locating the frequency and applying a sharp cut to it, but if you play the 78 it is huge and the resonance is all over the record.
As for other record companies' sounds, the sound of pathé/perfect around 1927-8, while a bit technically deficient, has an amazing nearness and intimacy that other companies just don't have, if you can get over the crackly surfaces!