That should be specified by the cam manufacturer. Their specification can be tightened up a bit at the strip for a hair more lift but for street use it would be a good idea to stick with what they reccomend.
The hot clearance may change with Aluminum heads vs. Iron too. Ask the cam supplier.
I've run 3 solids (although I can only find 2 cam-cards!) and the clearance varies materially depending on lobe design. In all cases the manufacturer specifies clearances when hot - the cold setting (which is not given) is quite different depending on head material.... aluminum and iron do not expand the same when hot.