When i did mine - 3300 not used for 16 months - the first few cycles were done at 1 amp - don't fully charge them - I let mine go in stages - 5 mintes then light discharge - 10amps (on Turbo 35) - then 10 minutes, and so on. Equalizing on a tray helped also.The run time was OK for practice - obviously no punch. I had 5 packs and only 1 cell that would not come back.
It was better than buying new packs for practice.
hope that helps.