That's a very detailed scale and very well constructed. It does seem a really useful tool and if it helps you better understand the points at which you can stop the thoughts or reach out for help, then yes I'd say it is efficient. I recommend that you share this with your T and any other medical professionals that have an interest in your mental health, then if you are finding it very hard to talk about your thoughts you can simply point to where you are and let them ask the relevant questions.

I'm very impressed by how many stages you have recognised and the level of insight you have. Just a thought and a little off topic, do you think you would be able to construct something similar that could assess how valued or useful you feel, something that would help you see your positive qualities even when your mood is really low? Your T might be able to help you do something like that.