There is a feature on plain bearings called conformability, eg its ability to conform to a non perfect circle, with its soft overlay the Trimetal is a better conforming bearing than Al/Sn.
However the death of Trimetals is only a matter of time, there are now better materials eg sputter plain bearings which eat away the top end of its market, and the Al/Sn's are getting better each year which eats away the bottom. Once these meet its curtains, its an expensive process with a production line costing Â£30 to Â£40M and only a few experts in the process.
I will look out for the book,
Some history on Glacierhttps://www.alpertonhistory.info/the-glacier-metal-company-limited/
Started by 2 guys from the US and they made Whitemetal bearings at first in the First World War, this would have been poured like the early Triumphs. Do not know when they started to make shell bearings.
They developed the first Al/Sn bearing in the 50's and called it AS15 as it contained 15% Tin, it was roll bonded onto the steel using pressure alone, no heat except from the action of the rolling press reducing the thickness of the 2 layers by 50%. This has been copied all over the world is is the most produced plain bearing material today.
Glacier was in direct competition with Vandervell who had licenced the Cast Trimetal process from Clevite.
To cater for customers who wanted the Trimetal bearing but to ensure they did not breech the patent held by Clevite they developed Sintered Trimetal bearings eg SL,SY,SX not the Cast of VP1,VP2 VP10
Owned by AE who then also later on bought Vandervell it became Glacier Vandervell.