If it's the same method discussed in the article mentioned below, you should be able to shorten the prolongations until it's akin to regular speech. The article also mentions that this technique is the most efficient for fluency shaping when analyzing past studies. In my opinion you don't have to speak like this all the time and use it only when you're about to block, using a cadence closer to a regular conversation. But it depends on the severity of the stutter and also needs practice, plus as the article mentions, the use of other techniques and work on the mental health side of things on how you perceive yourself and stuttering in general. It's an interesting article and if it peaks your interest it's easy to find the full version on the internet. Stuttering treatment for adults: an update on contemporary approaches - https://pubmed.ncbi.nlm.nih.gov/21080299/