I have not had any cauliflower that will hold past maturity at all. But
I live in a warm climate. I tie up the heads as soon I see the buton (
beginning of a head). They usually reach full size in a bout a week.
Check the larger heads at about 5 days and every other day there after.
You should have a smooth curd. When they reach maturity, you will see
formations like grains of rice, still edible not prime. Any further and
the individual flower stems will began to seperate.They head fast and
they tend be very uniform in heading. Size depends a lot on growing
conditions. If they reach x size and quit growing, no point in waiting
for them to grow more. Whatever they will do, they will do swiftly.