@jeff_strater asked what my issue was with creating User Parameters that have units. Please see this unlisted youtube video to see the issue: https://www.youtube.com/watch?v=f8ubuZwZZLE
I have since seen @HughesTooling's workaround to divide a user parameter by 1mm, for example, to make it work in a formula, but this seems like a workaround and is in no way obvious to a user.
I'm not sure what the solution is, but might it be as simple as just ignoring the units when user parameters appear in a field that needs a unitless value (like Qty in the rectangular pattern command)?
Thanks