Another option could be to have your template in an easily-readable format, such as a text file. Then the reading part becomes trivial, can replace your placeholders as they are encountered, and write to a pdf using pdf::create.
The reason I offer this solution as an alternative is due to the fact that I must be quite dense - I tried figuring out how pdf::reuse works, even looked at the PDF::Reuse::Tutorial, and have no clue how you could find the tags and replace them on the fly using that. I could just be a little low on IQ points, but I find pdf::create very easy to use...