On Friday, October 19, 2018 at 1:19:37 PM UTC-4, Ouroboros wrote:
Jonathan: I agree that the max weight without water shouldn't be relevant, but I'm not the one that needs to be convinced. The last two people to do weight and balance for this glider both used the number from the TCDS.

805-609=196 lbs max pilot weight.

How do I convince someone to ignore the number in the TCDS?

I would start by explaining that the flight manual provided by the builder is the controlling document.
If in doubt, ask Schleicher.
Then I would weigh all the parts and do the sums.
UH