Advice for Choosing an SCA Name
What is your best chance of choosing an SCA name that is registerable? First, talk to a knowledgable name herald. A good name herald will help you, or try to find for you someone else more expert in the culture and time you want to be from.
Next, try to pick a name as authentic as you can stand it. The more authentic your name is to start with, the better. If you pick a name barely authentic to the current standards, you may or may not be able to register it 5 or 10 years down the line. If you pick a VERY authentic name, it is probably going to be still authentic enough to register 5 or 10 years down the line. Of course, you can pick a name now and submit it for registration immediately, or pick a name and never register it, but nonetheless the more authentic your name is to start, the longer you will be satisfied with it.