So basically what knutor said, except make shields instead of bucklers, unless you're going to be using mauls or greataxes for some reason.
I don't know that the weapon makes much of a difference, Drazinonoda. Why do you say that?
I prefer bucklers to shields, even so. Armor raises faster in the danger room with bucklers. Shields cover more than bucklers, true. That means more blocks and less armor hits during training, doesn't it?
They also take half the material of a shield, so if weight matters for speed calcs, a soldier carrying a buckler will get to his prey a step ahead or first. Sometimes. It only takes one hit. Sincerely, Knutor
You are basing your choices on training scenarios, I am basing mine on invasion scenarios:
You are correct about the higher armor skill gains with a buckler, as well as the speed consideration. With training, either in a danger room or live practice (with captured goblins, say) these are definitely good things, as shield will raise quickly enough anyway and one wants one's dwarves to learn the other skills as well.
In an invasion, the considerations are slightly different. For example, there are few ways to filter out or neutralize marksmen among the enemy forces. I'll assume that the fort is laid out to force invaders to engage the defenders all at once in close quarters, to account for the speed difference of a single dwarf charging through a hail of bolts across an open field vs. an entire squad engaging the archers at once. At close quarters against a squad of archers (or worse, a squad of melee with an elite archer squad leader) the primary consideration is how many blows land, and while a strike blocked by a shield or buckler never causes injury, a hit against armor
often does, with copper armor being the most likely to allow injury by non-blunt attacks. In short, copper armor is only as useful as higher-grade armors when considered against blunt attacks, where all armors are about equally ineffective. If you have invaders coming in, then the fewer dwarves you have passing out due to chipped bones or dying from headshots, the better.
As far as the weapon thing goes, I'd thought that multigrasp weapons played nicer with bucklers than with shields, but reviewing the wiki doesn't give me anything to support that the game differentiates in function between shields and bucklers, so I'll have to retract that.