On the second link, you can find:
Cales de la presqu'île de Quiberon
And down after,
Cales sur le golfe du Morbihan
Larmor Baden and Crouesty seems to be the best.
The main problem, in summer, is to park car and trailor...
It's better to use slipways early in the morning, it's easyer to find places to park...