I have done my searches and still i am condfused. I needed to change my 1 inch treaded headset on my khs with a new hatta swan headset. I removed the race from the fork crown to realize that the original was a 26.4 and the one from the hatta was a 27.0. if i have read correctly

1. the hatta headset willl not fit since the cups are larger than my frame will allow. If i want to install i will need to bring the frame to a good bike shop to have them modify the headtube so it will fit the new cups?
2. if this is done what can be done a about the race for the fork? since the 27.0 on will not fit can i use a new 26.4 race with the hatta headset?

or should i just press the new cups in and use a new 26.4 race and call it a day?