Measuring floor length curtains

[happyfrogger]

Can anyone advise the best rule of thumb for measuring drop?

I'm advised to measure for double punch pleat from the bottom of the pole - is this correct?

Secondly, should I am for exactly in the floor, a couple of cm above or a couple of cm below?

They are for a smart bedroom bay - I want to avoid ankle swinging or tatty creasing / gathering in the floor. A big radiator may push the middle out just a fraction.

How do I not screw this up?

My pole isn't up yet so that may help but I don't have much to play with re pole shifting up or down because of heavy coving, so there is about 5cm play above.

Better to go long with the risk of having to take up?

Thanks!

[NameChange30]

Put the pole up and then measure from the pole to the floor.

[7to25]

I like to measure from the top of the pole to the floor, but I like the bottom of the rings covered.
Do NOT have them swinging a couple of cm above the floor...it looks horrible, like half mast trousers.