I know this is really just an experiment on recovery of a possibly 'dormant' battery, been there done that, but if the OP had been in the UK I would have saved him any possible disappointment and sent him a replacement at cost of postage only. I have several brand new Yuasa 12V 17Ah and 12v 38Ah batteries in my garage that are in A1 condition. I always like to have some in stock in case of need but give them a top-up charge every 3 months as recommended by the manufacturer.
I have absolutely no issue with people trying to resurrect sulphated batteries but from a commercial point of view, time is money and they are just not worth the time or effort and can never truly be trusted even if they appear to 'recover'.
As a side note, I also look after my cars batteries and it shows in the life that I get out of them. We do a lot of short trips, often with headlights on and rear screen heater running in the winter. The poor batteries have a hard life as a result as the starting charge is not recovered on each journey. I tend to 'top-up' the charge every couple of months. My Audi and my Wife's Nissan are still on their original batteries and both cars are from 2005. 9/10 years out of a car battery is easy to achieve if the battery is a quality product and looked after. Some owners just hammer the battery in this age of little or no maintenance and then wonder why they need a new car battery every 3 or 4 years, sometimes less. At the end of the day, it is personal choice. I am a electronics and communications engineer (in UK terms) and still believe in preventative maintenance, where appropriate. Some preventative maintenance can do more harm than good but that is another story.
I have just bought two new batteries for our cars, not because the old ones are shot, but purely due to preventative maintenance....why risk a complete failure and resultant stranding when the battery has obviously had a long service life (approx 10 years) and is due for replacement on those grounds alone. The old batteries will be looked after and likely gifted to someone in need of a spare or temporary replacement. The new batteries are from a local car parts supplier (Halfords UK) and are made by Yuasa, a quality brand, and they are decent batteries for around GBP60 each. Risking a complete battery failure for GBP60 would be considered foolish, hence the application of common sense. The old batteries owe me nothing
As a student way back in 1985-7 things were very different. I had a 1971 Mk1 Ford Escort (wish I had kept it) battery charging systems were not as refined as these days and the Escort had a D.C. Dynamo as the charge generator. The battery was so knackered that if the engine did not fire in less than about 10 turns the battery was flat ! I nursed that old battery for two years before finally giving in to the obvious. It was time to replace it. I had resorted to keeping the battery on charge overnight during Winter and warming the spark plugs to get it to fire up on a very cold morning with thick oil in the sump. Extreme measures, but when you do not have the money for a new car battery, you have to improvise. These days I can't believe I went so far to keep the old decrepit battery going......I doubt any modern student would do such and may even consider me crazy. Times change !
So when people talk about looking after Pb based batteries and recovering them from the dead, I know what you are thinking.... been there, done that, got the T shirt
I wish the OP well in his valiant endeavours to breath life back into the sulphated battery.....but please do not be too disappointed if/when you fail in that objective. As has already been said....maybe it will just be a case of letting it rest in peace
Aurora