Based on what Mike has accomplished so far I don't for a minute doubt that he could do this part of the job as well. The words of caution were based not on a lack of faith in his abilities but on the requirements of his building permit.
So seated firmly astride the devil's advocate steed let me say this about that. The requirement for a licensed contractor is there for his protection. It in theory provides for the job being done to IEEE standards with the proper materials. It allows him a path to protection by the courts should the job fail to meet those standards. It offers proof of compliance to local codes in the event that he should ever sell his house. And, finally, should he ever need to file an insurance claim for losses on the structure he has that documentation to support his claim. Having said that it's Mike's decision to complete the job as he see's fit.
We have the luxury of being able to sit on the sidelines and cheer him on and the reponsibility of doing that in a way that is supportive of his decisions, it's his build.