How to upgrade stator/regulator Daytona 600?

I have a battery problem: on a fairly long run last week, I lost all instruments (revs, speed...) and the bike wouldn't restart. I replaced the battery, but the multimeter tells me I'm only getting about 11V with the engine running.

Having looked online, I believe the problem is with the stator and/or regulator. 2 questions:

1. how do I diagnose the problem to avoid buying parts I don't really need?

2. is there an upgrade available for either/both of these parts?

Many thanks.

 

Great. Many thanks for the links