They should all be within about 10psi if its a very healthy engine.

yes take all the plugs out

standard figures vary a lot, not least of which because gauges vary so much (i have 3 gunsons gauges that read a 20psi out for the same cylinder) but I guess its going to be around vaguely 150 ish, ie it shouldnt be over 200 or under 100 at least, lol