1997 CR 500 Steering head angle change

[Iceman]

I am going to change the steering head angle on a 1997 500 steelie to tighten up the steering (make it the close to 250). The machine is used for Oval Ice racing.
My question is, what should the angle be changed to?
Or what is the degree difference between a 500 and 250?

I would like to build a AF conversion, but for a 4-5 race season and the there are no CR's or CRF's cheap in Canada, this is not a option at this point.

Thanks for your input.