Master 2S + Y arm sags

After doing a a routine to find the optimum focal height i noticed the arm with the laser droops down. the height at the starting position is 78mm and the height at the end of the arm is 70mm, which makes focusing difficult. I have the back of the frame screwed down, but it is still sagging. Is three some other leveling method to level the laser arm so the height distance can be maintained. Longer end supports would be great, like the competitors product.