Thanks for that link Mark. I'll definitely bookmark that chart for future reference. Do you know if those are open-circuit values? Because right now I'm using them as a reference with them in the tractor (obviously) and disconnect on, which would be a small, relatively negligible load.
When I got home from work last night around 5:30, I metered each battery and the whole pack. Not sure how long the charger had been off since the last cycle from the controller, but individual readings were 6.39, 6.42, 6.40, 6.37... all indicating a 100% charge according to D&D's chart. The overall pack was sitting between 38.4 and 38.5V, also indicating 100% charge. So I set off to finish the yard and it seemed as if the tractor was running as expected after about an hour. I was doing a lot of trimming under pine trees the last half hour or so, but will have to post again after starting the yard from scratch. Plugged the tractor in after finishing and at 10:30PM when I closed up the garage, the controller had stopped cycling to about every half hour already. Hoping for better results next week, as i'll be out camping through Monday.
I will offer this to others that may not have the equipment or know-how, but for those that are running controllers and need them adjusted, I would gladly do it for free if you pay for the shipping back and forth.
Thanks everybody. I hope this helps more than just me.