My first and probably not the last mistake. I misread the plans and measured the positioning of the float chainplate from the deck glueing flange in stead of the top of the deck. Now the chainplate is sitting 1 cm too low. I'm nog going to correct it (it is impossible without doing a lot of damage to the float). I'm sure it will still be possible to attach a stay to the chainplate.
I will put the chainplate on the second float also 1 cm too low - I want the floats to be identical.