Personally, I like to give a nickname to all my dwarves which is simply the year that they arrived. With this, I can keep track of how long they've been training. Right now, my "a5" (a=arrived, a migrant) dwarves are still individually training, as the year is 6. When it becomes 7, I'll switch them to active duty so that they spar and get the cool (well I think it's cool, anyway) filled-in dwarf smiley icon denoting a soldier on duty. I'll leave them that way for one more year, before I start activating labors on them.
I make a few armor stands to start and place them near my entrance. Then, I just make a squad once the first migrants come and are nicknamed, and assign them no specific uniform or weapons so that they just wear the clothes they came in with. Also, I disable any water/booze carrying and food carrying, for simplicity. Since I'm mostly looking for my dwarves (in general) to be better workers/haulers/wild-animal-attack-survivors rather than killers, I don't bother with weapons until I make an actual standing force, although they are rather adept at taking out the odd band of gray langurs... Anyway, I set the armor stands to be a barracks, and set the squads to use the barracks to train. I usually just leave the stands outside, to put off cave adaptation.
Dwarves typically don't spar as frequently at lower skill levels, from my experience. That's why I just have them individually train for the first year. I hope that this experiment turns out well, and if it does, I can see myself doing this in all my future forts. It's a fun game of checking your dwarf's attributes every couple of months and seeing them progress.