Circuit height joins are really a no-no unless 1) local instructions dictate otherwise or 2) ATC (if present ) instruct you otherwise.
However, for the vast majority of uncontrolled fields (and I include FISO units amongst these) again -
unless your Bottlang / Poooleys / VFR guide says otherwise the following should apply.
Overhead at 2000' (top of the ATZ effectively). Check for other traffic, descend deadside.
Cross the upwind numbers at circuit height, turn downwind when in the correct position.
Easy
CM