When fitting our new "Space Capsule" handle bushings into your CB500T there are a few differences in it versus a standard CB450 triple tree. Honda changed the starting diameter of the taper that the bushings fit in on both the top and bottom of the triple tree. This causes the handlebar bushings to sit significantly further down in the triple tree as you can see in the image below.
To compensate for this, you might need to add a few M12 washers on top and/or bottom of the handlebar riser to further space up the riser and not run out of threads when tightening the nut on the bottom. Without the extra washers, we have found that the threads bottom out before fully tightening the handlebar risers on the CB500T. Message our support if you have any further questions.