adjusting the lash hot has been important in my experience. others have differing opinions, but my reasoning is: when the engine is at operating temp, it is within a fairly narrow/specific temp (provided your cooling system is functioning properly). when it's "cold" you don't really know how "cold" it is - can be a relatively large swing depending on ambient temps. get the car good and warmed up, leave it idling while you get everything ready (blanket on the fender, 14mm and 17mm wrenches for valve adjust, 10mm socket w/extension for valve cover, large crescent wrench to turn the cam, feeler gauges set up (.010"/.25mm intake, .012"/.30mm exhaust), plug socket & extension, then when you're all set, shut her down, pull the plugs, valve cover, start at #1 and work your way down the line. you should be able to slide the correct feeler gauge in with a light resistance and the next size up should not go in. remember that the clearance gets tighter when you torque up the lock nut, so you need to back check every one as you go. once you get the hang of it, you can do all 12 in about 10-15 min.
set 'em right and she'll run nice and quiet.