Paperwork needed when buying a boat and making some changes...

[Kwik Decision]

Don't worry about sail numbers. For club racing and RTI you don't need it.

You certainly do need a sail number for the Round the Island Race. The rules require it to be displayed on Dodgers as well as the main, but quite a few boats don't bother with this......

 

[Tranona]

Although if the OP races a bit his idea of properly set up will involve a bit of pre-bend and rake not to mention using the backstay for trimming, so that's all working against using in-mast furling.

I know all about that, but when you choose in mast it is a deliberate choice so are aware of what you can and cannot do with it. If you don't like those restrictions, then like the OP make a different choice. Not sure how that "works against" in mast. The two systems just have different characteristics.

The odd thing is that Bavaria fit an adjustable back stay irrespective of which mainsail type you choose. The one on my 37 was never adjusted except when the mast was dropped.