mctow for the dhc6 twotter is 5669kg but that can vary depending where in the world the job is. Some countries use higher more realistic numbers :-) V speeds, would be a dick nuts thing to be asked, thats what your ground course is for don't worry about it. You'll absolutely love it I guarantee. Specially if it's operating into anywhere seriously short
Havent seen any twotter spotter stuff on the net sorry, but then I never looked.
19 seats, 2 pt6a-27s (dhc6-300), big f***off flap system, thats all ya need to know.