Tip: After editing your overworld, make sure to use an EMPTY save file, as save files with progress may load Mario's position based on previous versions of the overworld. Note that altered level flags will also only take effect on new save files.
This patch lets the user decide how many wigglers are supported on screen at any given time. It also makes them not reliant on sprite header 0A in order to work, meaning that you could use them with NMSTL or SA-1 Pack without issues.
Small, uninteresting note for SA-1 Pack users: The header feature is going to be added by default in future SA-1 Pack versions (1.41), unless you want to modify the wiggler limit you can ignore this patch.
Rejecting this due to a bug when you set !wiggler_amount to 5 or greater. Returning with an index of at least 4 to the main routine will cause it to read past the ends of the tables at $02EFEA and 02EFEE, causing the wiggler to use an unintended block of RAM as the segment buffer. In particular, setting a max of 6 wigglers (on lorom) will hit Map16 data, and using a long enough level will cause something like
Other than that, everything looked okay. Changing sprite header worked well, which is certainly nice to be able to do.