My opinion would be go simultaneously. It's no use in having the "techniques" but not exposing yourself to situations where your stuttering can produce itself, and also for some people dragging themselves in anxious situations without the "techniques" would be too much. And you can see it in a person, I for example, don't benefit from almost any of the "techniques", it just restricts my speech and teaches me to talk with a crutch, which is more control which sooner or later leads to stuttering. So I'd benefit more from cognitive behavioral approach while for some people the anxiety/self confidence/exposure is not the issue, they may be more in need of the "techniques".