OK, so I used X-scale instead of Height, and I divided by 100 to get the percentage, and it works great. Thanks, Brian, this is some good stuff.
What I'd like to see is perhaps some more string functions, or a bit more clarity in documentation. Maybe a string Length function would be helpful, so we could do some things like cutting off some part of a string without knowing its length or specifics of its contents going in, but, in this particular case, your solution works fine.
#XPression