What’s the best level for farming level 3 combat manuals?

Map 1, chapter 20 "westwinds"... lvl 9.. only costs 16 AP will get you more lvl 3 blue combat manuals... the last map that only costs 10 ap is good too, but I find westwinds a lil better

Basically, the level that keeps giving them. As you progress, you keep getting better and better prizes. At campaign level 15, you will get 1-5 of each item for 1* thru 3* and light 4*, for example, whereas early on its just light of a single item. You best bet is to just keep going and use blitzes on your previously defeated stage when you lose as you level up heroes to try again. If you cant level up and are waiting on pieces, just keep those blitzes going if you have the tokens