More templates for derivative works

[VarunSoon]

I would like to create templates for derivative works based on work types other than the ones (operas, psalms, and carols) already with such a template ("OpDerivs", "PsalmDerivs", and "CarolDerivs"). For example: "Template:SymDerivs" would allow including "Based on the Allegretto (2nd mvt) from Symphony No. 7, Op.92 by Ludwig van Beethoven" on the page "Fantasia on Beethoven's 7th Symphony, Op.39 (Thalberg, Sigismond)" while also putting that page into the category "Pieces based on Beethoven's 'Symphony No. 7', Op. 92".

My inquiry is with the fact that the source code of 'OpDerivs' and 'CarolDerivs' are quite different, so I am not sure which of these two templates to base the new templates on. My guess is that, since I want to include the ability to specify which movement of the work the piece is based on, I should use 'OpDerivs', which allows specifying specific song in an opera. Which one do you think I should use?

[cypressdome]

The OpDerivs template had a major redesign several years ago that simplified what a user had to add to the template in order to add a new opera. It calls on the template OpDerivs2 to handle certain formatting and to automatically create the new "based on..." category. The CarolDerivs appears to follow the original design of the OpDerivs template and if you edit it you can see how much more has to be added and in a very specific format in order to add a new work. I would say OpDerivs/OpDerivs2 would be the templates to follow.