At what age should I start building drive I have a 6 month old American Bulldog. She doesn't want anything to do with the tug until I start working my older male. SHe will play with a rolled up towel but is not as intense as she is when playing tug with another dog?

Ok, first off, have you watched the video fully?

The method that Bernhard trains in requires at least a genetic level "5" in prey drive to work. Some breeds have lower prey drive then others, and there are low prey drive dogs even in breeds that are normally on the higher end of prey drive.
If your dog has low prey drive to begin with, the Flinks method will not work well with her.

will remind me again how we can know what level of prey drive our dog has on the same scale (flinks), i know i should know this, but i cant remember.

Ahh, not to worry - your intial reading of a dog's drive should come from the puppy test. Ed has a good description of what he's looking for at:
http://www.leerburg.com/pickpup.htm
And the Flinks score sheet for puppies is at:
http://www.leerburg.com/scoresheet.htm

Bernhard trains his dogs in drive, so the prey drive is the "5" that we're speaking of.
For an older dog we're looking at how strong his desire is to chase/ grab an item/ toy that's in movement. Use a favorite toy of the dog and put it into prey-like movement. How hard and long the dog will work for the item determines his prey drive level.

Will, on a older dog say 2 or 2 and 1/2. I watched a female GSD chase a flat soccerball all day and would search for minutes looking for it. She will tug with the ratty old soccerball (I tied a leash through it and work her like you would with a ball on the string)has great grip . She has Itor type focus you can walk up and pick her back legs up like Bernhard Flinks does but not as high. Once you get her back feet waist high she looses focus and looks like she wants to bite ya. How would you transfer that focus and move her to bite equipment? Personally, I think she would make a good dope dog. She's never seen a tug I could get her to chase and bite tug. She would fetch it and but she only half hearted tugged nothing like when using her ball.

i understand the flinks test sheet and i have the bitework for puppies video. i understand what prey drive is, its how do we gauge prey drive without seeing a dog so that we are on the same scale? for instance the longer the better, the harder the better, however how long is great how long is good how intense is a so called "5" in prey drive and etc. most people understand what prey drive is however they dont realize unless they have seen plenty of nice dogs that they might have a lower prey drive dog that they once thought was over the top. for instance my puppy will chase and strike a peice of leather tied to a horse whip for a long long time, i have never had him stop yet. when he strikes to bite the leather and misses his teeth make a loud clap everytime. i can also just hold a peice of leather or a towel or basically anything and he snaps at it clapping his teeth while jumping through the air. he is 4.5 months czech import from the egidius kennel. he is still settling in, but he is warming up nicely. he already looks a lot like itor in the building drive focus and grip video minus the attention span and length of drive. i know he has prey drive and i know that he has pretty good prey drive, but i dont know what i would give him on a scale of one-ten when you consider all of the good dogs out there. its more of a comparative problem versus a definition or understanding problem.

Yes I did watch the video through more than once My main concern is that I dont want to push to hard too soon she will go after a rolled up towel like crazy I am trying to transfer her over to the tug but she doesn't want it unless the other dog is working with it any suggestions would help or should I just wait till she is say 9-10 mos before I really start to work her prey drive

If she likes the tug when she sees the other dog playing with it, use that to your advantage...
Put her behind a barrier or on a back tie and then play with your OTHER dog while she watches. Maybe then every once in a while let her 'almost' get the tug...
Do be aware though that at her age her adult teeth may still not be all the way in, so she may prefer the towel because it's softer and easier to bite. If she does bite the tug I would let her win IMMEDIATELY and make a big deal out of it.. praise and tell her how great she is doing.

I would just keep on working the prey drive, if she goes crazy for the towel then you know she has the drive. some dogs just really prefer one toy over another. It may just take time!

What is your goal for her long term? Schutzhund or ?

Iron Dog and hopefully Mondio or some other ring sport and then a catch dog title being both parents were used for this