Sounds like a solid approach! Personally I've seen the best results with desensitization, when I've truly not cared about the outcome. It's much easier said than done and requires practice, especially if it's a habit built over a long period, but certainly possible to learn to shift focus on the idea rather than towards a foreseeable block.   I don't know about others, but whenever I'm temporarily angry (sometime cuts me off in traffic, etc.), the focus shift purely on the other person and the message itself, and not how I'm going to pronounce my next word(s). Not suggesting to be angry all the time to start speaking fluently, but an interesting observation of the effects of speech during intense an shift in attention away from speaking.