Here are the results of SCIENCE after a half-year of training (mid spring through arrival of the 1st caravan in late fall). All dwarfs trained full time and had no military skills to start.
2-man squad:
Expedition leader: Proficient Axedwarf; Talented Fighter; Dabbling wrestler, striker, dodger
Axedwarf: Proficient Axedwarf; Talented Fighter; Dabbling wrestler, striker, dodger, biter
7-man squad:
Expedition leader: Adequate Axedwarf, wrestler, striker; Competent Fighter; dabbling biter, kicker, dodger
Axedwarf: Adequate Axedwarf, wrestler, striker; Competent Fighter; dabbling dodger
5 wrestlers: On average Competent fighters and Adequate wrestler/strikers
What did we learn from this experiment? It was inconclusive because I didn't have 7 axes!
This diluted the skills by cross-training in axe and wrestling. I will need to repeat the exercise again with 7 axes (or all wrestlers) to make a more accurate comparison.
One thing I can say definitively is that a large group of unskilled recruits can be easily trained to competent fighters in half a year. (With starting skills and/or a good teacher, they'll train even faster.) Therefore I really don't understand the "training is too slow in DF!!!" criticisms. What is the correct number of months to become a Competent fighter in your opinion for this criticism to go away? 5 months? 4 months? 1 month? A week? A day???