As a new IMC pilot, not sure I'm qualified to answer, but I'll give it a go anyway...
Sounds like the problem is your situational awareness. If you know where you are, what direction you're going, and where you want to go to, and can draw those things on a chart without thinking about them (you don't actually need to draw them on a chart, just be capable of doing it if required) then it should be obvious whether you need to turn left or right.
To me, figuring out where I am is much easier than remembering lots of rules and equations about how much to turn and in which direction. Also, this then works whatever nav-aids you're using, it's not NDB-specific.
FFF
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