You answered your own question 🙂 You do NOT want to visualize any words. You are not visualizing crutches or words, you are focusing your attention on them. There is a big difference between visualizing something and concentrating on something.
If you are going to think words, be it part of a word, a full word, or even a letter, you WILL stutter. You need to stop thinking words and ONLY think crutches. The next time you catch yourself wanting to use crutch 1 but end up visualizing the word, or part of the word, force your mind to focus on the crutch and not on the word. You need to speak immediately. As soon as your mind forms the word you would like to say, speak. Do not hesitate, this way you can not think of the word. It would also be helpful to focus on crutch 11 at the same time – speaking like a King, as it seems that you think you are focusing on crutch 1, you are in fact focusing on words. Focusing on 2 crutches at once may help this in the beginning, because it is going to be extremely difficult to think of dropping a first letter/syllable as well as speaking slowly and with pauses and STILL think words.
I hope that answers your question, but if you want me to explain this in more detail, email me at email@example.com and we can have a quick Zoom session.