MV rectifier choices among those who made rectifiers and equipment

[Opcom]

This is trivial but it's a nagging question.

Some rectifiers are electrically identical and practically the same height, having only a different sized base.

RCA made the 872 and the 8008.
Some transmitters use the 8008 and some use the 872.
Those are the same except for the length of the pins.

Another example is the 673 and the 575A.
Those are the same except for the diameter of the base.
(The 575 has a different envelope but it is in some ways to the 575A like the 866 is to the 866A)

What factors would have gone into the choice to use the 872 or 8008 in a particular RCA transmitter? It would seem that the engineers had a free choice of either tube which were made 'in-house' and the cost should have been the same within a few cents at a time when the average 1KW transmitter would have cost about $6000.

Secondarily, why would there even need to be two tubes identical save for the base? I see no advantage between the Jumbo or super Jumbo bases -either is perfect for a 10-15KV rectifier.
Were any of these first made by other companies whether for themselves or as a "foundry contract"?

[W7TFO]

The super jumbo base (straight in socket) was brought out by Westinghouse.

The UX base (twist in) was by RCA.

It gets really confusing in that Westinghouse built things for RCA before they had manufacturing facilities....

73DG

[k4kyv]

One problem with the twist-in socket is that sometimes the base will come loose and you may pull the wire out of the glass envelope, or even break the tube, when trying to remove them.  If a tube has been in service for a long time, I check it as I twist it, and if it appears loose, I try to fabricate a tool to grip it by the top of the metal base and take some of the torque off the envelope-to-base bonding material while rotating it. A squirt of WD-40 round the inside of the socket metal base sometimes helps, since often the problem is corrosion between the socket base and the tube base.

The Gates BC1-T uses the 8008.  If I didn't have the solid state  replacements, I probably would have changed out the  sockets and used 872-As,  since I have many of those but very few 8008s.