He doesn't seem to use the Palmfret and the normal frets at the same time on the same string, so confusion over pitch may not be that great. See here: https://youtu.be/po8uUGX4oIQ?si=HXX30wGko_toNjuw.

The system used on many arch lutes and theorbos looks so much more elegant and simple to me. They just added a scale of individual strings for bases. Simpler and perfect for muscle memory.