And which edict helps with that?Exploiting basetax
Sure, and if you are in position when you actually need slacken, you should've probably activated manpower edicts at this point. However, doing it for the whole country is not a good idea, as you may need defensive edict or edict of absolutism (in case of blockade), or just develop some province, and you won't be able to enable another edict before 1 year period expires. It would be wiser to enable edict only in provinces which give you the most of manpower, and those you where you don't plan to use other edicts soon., slacken recruitment
Do you do it in really random manner all over the country, or choose a few provinces where it's the most efficient? I guess the latter makes more sence., randomly deving because point cap.