Ok..

The question was .. "Most stable.. 10'.. and mostly Flat water (90%).."
Then why answer with things like If she's only 60kg you don't need a board that size.. Or this board surfs better.
Or even mention a 11'4" board.. (btw the 10' Mama is much more stable than the 11'4" Nalu).. Good idea suggesting the secondhand boards but cheap or secondhand wasn't in the question ..

I'm thinking he/she wants a very stable board that no longer than 10' and mostly paddle flat water...

Maybe she wants to do yoga on it.. Maybe she wants to be able to paddle two-up or with small kids.. Maybe paddle with a large dog on board.. Who knows.. Maybe even load it up for a sup camping trip..

.. Or just a super stable fun board to learn on.
If the question was for a board that was for mostly surfing with some flat water paddling I would have suggested different boards.. (like the Whopper.. It surfs great) or even suggested a shorter board to get better surfing performance.
Also a 60 kg girl carrying a big wide sup is going to need a good handle.. Like the Naish or Coreban.. That's partly why I suggested those boards.. The 10'2" was just a cheaper option.. That JP 9'9" sounds good but I was only recommending boards that I know about and that I've used.. I'm sure there's plenty more good suitable size boards out there.. I'm thinking that JP might also have that great Naish handle.
I'm not complaining about anyone or their answers or ranting.. or even pimping brands.. Just saying what I'm thinking ..

.. and pls don't anyone take it personally..

DJ