The 250 is the better bike to start riding on. Starting on a 600 can be done. It isn't advised for several reasons but it can be done. All that is moot however.

The blocking point here is your father won't let you have a 600. Skill, danger, respect and etc are immaterial. Best we can do is give you advice on how to win him over. And btw

http://www.youtube.com/watch?v=i7x6LWP1FKE

Prolly won't help when your dad sees that But the point I'm trying to make here is that the rider controls what is / isn't done on the bike. An irresponsible rider can kill himself on a mountain bike.

 

Wow look at the little 250 go :P

 

You can clutch up any bike. 80 MPH was prolly near the top end on that bike

 

That's pretty cool not gonna lie.

I've played around with clutch wheelies before - its slightly frightening.

 

Found power wheelies more frightening than clutch ups. Higher speed to start them out and easier to hit 12 o'clock+

 

Oh wow, definitely gonna use the anology of the mountain bike Kuroshio, but that video I think is gonna stay out of the conversation...wheelies will never happen with me, I don't have a death wish, just want to ride, but look and sound good . He continues to say its not me he worries about, but other drivers and hes convinced I'm gonna die. This is why, I cannot wait to leave the house and all the B.S. my family brings with it....