Sparks plugs are 14ft pounds. or for me I spin the plug down with only the extension the turn my 3/8 inch ratchet about a quarter turn to get firmness and also to crush the spark plug washer slightly. Then I just put my hand over the ratchet head over the tighten or loosen switch. And just twist as *bottoming the ratchet gear without twisting any harder. It comes out to 14ft pounds. Of course I would not know with a Snap on brand Ratchet as some of them have 50 gear teeth in the head of the wrench. Where my is just a cheaper one like most affordable wrenches 30 gear teeth.
*just turning the wrench tight and bobbling between the gear teeth without hearing the ratchet click but one time or so.