Do It Yourself (DIY) Not So Cheap After All

You didn't include your time. Maybe you could have been doing something else like drinking beer or watching a hockey game. OTOH maybe you built it while drinking a beer and watching a hockey game.

My DIY guideline for anything in the house or on the car is: "How expensive will it be for someone to come and fix whatever it is that I've screwed up and how long will it take me to screw it up?" Anything > $500 or 2 hours and I get someone who knows what they are doing to do it.