Hi Bush rider,
Where abouts do you live? maybe one of the more local racers can help as the conversion is always difficult with front ends! you may require bearings to be modified so be prepared!
A CG 125 is not a bad front end to use, but I note that a lot of people are using RS250 Honda (the early single cylinder four stroke road bike) forks and discs and these seem good for racing.
Cheers,
Alan
PS: Tonys article in the main bantam racing web site on building his 175 racer