You need two gauges: a .006" "go" gauge and a .008" "no go" gauge. When the valve is adjusted correctly, the .006 will go in and the .008 will not.
feeler gauge
0,25 both regarding to the BOOK
.022 gap with a feeler gauge.
0.03mm is the least count for feeler gauge
26-30 degree dwell or adjust points to .017 with a feeler gauge.
the thickness of a paper match stick is real close.
not that critical 0.8mm or if you dont have feeler guages the back side of a hacksaw blade will do ( the side without the teeth) the standard contact breaker gap is 0.12mm - 0.13mm rotate the rota so the points are fully open then insert the feeler gauge realese the locking screw so that it shuts on the feeler gauge then lock the screw off (just nip tight as it can break real easy)then remove the feeler gauge then your done. i know this as i have done so many.
It varies from manufacturer to manufacturer, but if you have a feeler gauge, try setting it at 0.011 to start, in a pinch a matchbook cover or business card will get you really close to the appropriate setting.
Some spark plugs come pre- gaped depending on the vehicle and type of spark plug. But even pre-gaped plugs should be checked with a feeler gauge to be sure it is correct If the plugs you are using are not pre-gaped a feeler gauge must be utilized in order to get an accurate gap reading. Your local auto parts store can help you with what the gap should be for your vehicle.
to measure spark plug gap
A .020" feeler gauge.
Use a feeler gauge to set the point gap at .016. .016 inches using a feeler gauge, 50 degrees dwell on a dwell meter using a 4 cylinder scale plus or minus 2 degrees (8 cylinder scale set at 25 degrees plus or minus 2). If the dwell is too high the points are too far closed. A dwell meter is by far the best method, but the feeler gauge is good to get you in the ballpark with new points.