On the topic of L.A. longevity...
I just started processing a Japanese 38B19L ,35AH auto battery for subcompact cars.
Initial volts = 5.6, Sp. Grav cell 1 to 6 : 1115,1120,1130,1120,1125,1120.
Internal resistance > 20 ohms.
I am 6.5 hours into the process and the Sp.Gr. is now : 1140,1150,1175,1155,1155,1135.
Avg charge current is now 4.64 Amps; 42°C <Cell . Temps < 48°C
Battery voltage @ poles = 13.82V, mild gassing has begun in ALL cells.
19.34Ah capacity charge delivered. Charge eff% will be low until 'normal' SG levels are restored.
FLIR imaging of the battery reveals no unusual hotspots.
From my prior test data, I can predict that this battery is going to recover significantly. I will know it's true capacity/capability when I test it using my hackaday AH logger project.
https://hackaday.io/project/1375-lead-acid-ah-capacity-testerlogger
EDIT: 20 hours of processing gets to SG's of 1265,1272,1280,1270,1273,1270 (a 15pt spread) and an internal resistance of 12.1 mohms or about 413 HCA which is ok. My estimated Ah is about 17Ah or 50% of rated. I'll do a full Ah test today as my method for Ah estimation is still being tweaked.