I’m way out of date to recommend anywhere as I did the course sometime back in the last millennium! The weather doesn’t seem to have changed much, though.
As far as measuring cloud
base, posh airfields have one of
these but if you need to do it manually you can use a combination of experience, guesswork and 400x the difference between the temperature and the dew point, if the air is well mixed up.
Cloud
ceiling, which is the legal definition of the height of cloud above an aerodrome, is the height of the lowest layer of cloud that covers more than half the sky.