Toggle Switches

So I needed to come up with a solution to a settings page, where the user can either use a px value, or a % value to set the width of an object.

Doing it the way that can be seen in the shot, I've come across two problems:

• When the left input is enabled, should the toggle handle also be on the left? Or should it be on the right as seen here?

• Should the user see both values, or just one like this? (If I showed two values, I could validate them to make sure that the % value doesn't go over 100%.)