Do yourself a favor, and get someone to do seamless gutters for you.
The company I purchased the exterior products from (roofing-siding-soffit) is a supplier of nearly everything for the exterior.
They have a truck mounted unit and will set up on site and run-off gutter to your desired lengths...Then they sell all of the hidden hardware for the installation. Even a leaf screen system if desired...
Using them will allow me to bypass any labor from a subcontractor.
I figure if I can do the groundwork...the roof and all other encompassed framing and coordination maybe I can handle hanging the gutters too...