Hi,
I'm an expert delphi programmer with high skills in document processing, including PDF, OCR and image processing, I live in France and work as a Software engineer.
The ideal solution for your need should be to use some "xml" or "json" template, to define the pdf layout, then use the code to set value and save it as PDF, this will ask fomr some work but it's usable for any other project about pdf generating.
For the immediate need, i can deliver you such code with TTMSFMXPDFLib, the result will be generator class which include function to add items, then the function code which will use the class generator to build your template (pdf), the idea is to have some abstraction between the subclass generator and the main code function, the class generator can be used of course later on any project as it's generic, it willl contain function such AddCutomField(AFieldName, AFieldValue). The idea behind all this is what you asked for : flexibility and ease of use.
Please feel free to contact me to dicuss about the project, it ll be a pleasure.
Regards.