yes, dynamic, so if you don't add a preset, then you don't allocate space for it.
code - its in the java code, not the firmware. but bare in mind if you start editing the code, then you will have to keep it up to date, when we release a new version.
as an alternative - think about 'templates'
create a patch that you can save useful code in, this could include a sub patcher than has everything set to zero.... then you can just cut n paste this into new patches where you need one.
(use the new favourites directory to save templates in , so they are quick to get to)
this has the advantage you can have different defaults, or pre-made bits of code for all sorts of tasks.
pretty similar to the concept of 'snippets' in Max, which I find surprisingly useful