In preparation for the second discharge I tried charging three different ways.
First I charged at 34A till the first cell hit 3.55V
On turning off the charge, the voltage immediately dropped to only slightly more than the starting voltage.
I next charged again at ~7A, and the pack voltage again rose to the 3.55 and dropped out, only to show the voltage again drop to a lower value, but higher than the first rebound.
Finally I set up two constant voltage supplies for 3.53V, and let the charger stay connected until the current drops to near zero.
After removing the charger, the voltage stayed at the 3.53V
Hi current charge gets you to the target fast, but then you have to hold the target voltage until the current drops to few ma as the cell fully charges.
Probably better to approach it more slowley, at a more moderate rate.5-8A may be a nice number.