Servo Torque
Well Now.....speed is going to be really tough.......but perhaps you could compare it to a servo that you do know the speed of.....
If its a ......say a Futaba 148......its going to be pretty easy to see the speed vs. a servo with a .12 or so time..........
Torque......You could place a one inch servo arm and hang fishing line from it......Start loading it down with large fishing sinkers.....this could give you a possibility............
Nylon gears vs metal gears could give you a clue............
I'd be careful where I placed them