1. Under military screen, equipment, highlight the wrestler in question, on the screen to the right, remove individ choice, type W to add a weapon of your choice. Unless you list a specific material, or a unique weapon in the stockpile, they will immediately go grab a weapon of that type.
2. The marksdwarve problem is easily solved, once you under stand the order Train. When you set them under Active schedule on alert screen, leave military screen, return, highlight that squad then type s to look at their schedule. To begin with, you will have only 2 schedules, Active, and Inactive.
On the active schedule, every month has Train. This means that they will give demonstrations, spar,combat train, watch demonstrations. In your case, having two out of three, the third one with nothing to do, if it has bolts will do individual combat drills, for markstmen means weapon train(target practice). So now, all three are not getting much target practice in.
Under either schedule, months that have no order,when any one does not have a job to do, will go target practice, as long as the bolts hold up.
So, a good schedule for marksdwarves under Active Schedule, on that yearly schedule is set 1 months order to Train, following two months no scheduled order. Repeat sequence for following months.
Train order is still good. They can get dodging, shield work, miscellaneous object lessons.
When they run out of bolts, and you forget to produce them, least they will be training/individual combat in something. For bonus points, assign them a hammer when they get somewhat skilled in archery. They will train in hammer if no bolts are available. When they knock the poop out of a gobbo with the bow(BAD), least now they will be better skilled in it. You can always remove the hammer if you notice that they are practising with hammer, and not archery