usable capacity of 35.8kWh battery?

I know the nominal capacity of the newest e-Golf battery is 35.8kWh, but I assume there's some margin on both ends for the sake of battery health. I guess I have two questions:

1) How much kWh capacity is actually represented between 0 and 100% on the fuel gauge? I realize this could be roughly calculated using the miles driven and mi/kWh statistics, just wondering if someone has already done that work.

2) How much margin is there at the top end? I've read it's not great for EV batteries to be at 100% so I'm planning to only charge to maybe 80-90% in daily use but I'd like to know how much of that margin is already accounted for, if any. This one is probably more difficult to answer.

Usable capacity is probably around 32 kWh, based on my experience with 2015 e-Golf. The fuel gauge only indicates state of charge (SOC), not capacity. If your 1/2 degraded battery is 100% full, then the gauge indicates 100%. I believe 100% on the gauge represents 97% actual SOC, based on OBDEleven data. Yes, charging to 80% max routinely will pamper the battery-this is what Tesla recommends. Only charge to full for long trips and only keep at 100% for a short period prior to driving (use charge timer).
So I believe there is 3% margin at top and 8% at bottom.