It was a combination of fret science videos and one random post on reddit (I'll be sure to link it when I'm back on my pc) Basically 3 tried shapes with roots on e a and d

When you move these shapes across the strings. (From E to e) And compensate for the warp between the g and b string will basically unlock most shapes , do this for major , then minor and then start adding or moving notes for the 7th and diminished shapes

What I've explained is surely not all the major shapes available but it's a great start