I would think that you can get an aluminum gyro GTX and machine the openings a little bit wider without any repercussions. The Gyro, if you look at the way it works, actually free floats on the head tube. It is not connected to anything, so the main thing you want is for it to be larger than the tube it is going around.
You will have to work out an upper and a lower cable stop though.
Look at the photo below and you will see 5 distinct parts...
an upper cable, the upper plate, the actual detangler, the lower plate, and the lower cable