Unless said "handyman" has being doing that exact work for years and is a Subject Matter Expert, maintains a license for that sort of work, and has a small army of knowledgeable workers to help with the installation, what you're going to end up with is an interminable project that tears up your house and might come in slightly cheaper than just hiring a company like Harp in the first place.

Also, the building department for your town/city is going to want to inspect the completed work. Think about that.