KK,
I have a 79/80 250 which has the older style motor similar to yours. These specs were used in a 36mm Mikuni I ran for 2 years.
Main - 290
Pilot - 35
Needle Jet - Q-2/159
Needle 6DH2
Slide - 2.5
Another contact from the NSW KTM crew gave me - Main 290 Needle 6DH7 or 6FJ6 and a pilot of 45 to 50 but I haven't used those settings.
I did have a 40 Pilot but it ran 100% better with the 35.
Pete # 100