Where to recruit new warrior monks?

[Jarmam]

I pretty much exclusively recruit Monks from provinces with +5 armor for a very simple reason: That's all they're lacking

They don't need +xp cuz if they close against any unit that isn't a Katana Samurai they will *demolish* it even without Warcry. This also makes them rank fairly easily as you can pitch them against legions of enemy Ashigaru or against their top-notch units and they will fare excellently against both. Also xp seems to equilibriate roughly around 4-6 xp ranks as this is where gaining more xp takes longer than the replenishing xp diminish will drain your xp ranks. Thus you will either have r7 monks for a few fights and then r5'ish or r2 monks with +4 attack +2 armor for a few fights and then r5'ish with all their added stats from +weapons/armor.
They don't need +weapons cuz if they get close against yada yada yada...
Their only weakness is getting close to the enemy in the first place and landing as many Warcries as possible (aka lasting).

So to me it sounds like what you want to rely on is Naginata Samurai as they already have solid armor and can benefit from the added killing power of +4 melee more than a Monk squad can (if I understand the stats correctly). I'd still add 2 Monks just for Warcry alone but I'd rely on Naginata Sams. Archers is a very personal preference thing, I know of a few people on this very forum that advocate heavily for Samurai Archers whereas I always switch to Monks the instant I get the chance. Go with your gut.

[Jacobin]

Found the bows did very well as long as I micromanaged them to stay at their maximum range but that the naginata monks were largely useless.

They did fine in melee thanks to their high defence but it was missile fire that killed them remarkably quickly.

And even +5 added to the base armour of 2 (the same as yari ashigaru) still makes them absurdly fragile given that you probably won't recruit any until quite late in the game when every AI enemy stack has hordes of samurai archers.

So I think a couple of bow monks and a single naginata monk unit as as last resort reserve will be my maximum.