I was looking into doing this but using 1/0 for the main pos and neg, then 4ga for the others. Got some prices on Amazon. Somewhere around $150
https://www.amazon.com/gp/product/B01MD1XRSL/ref=ox_sc_saved_title_2?smid=A2TN19FHI2Z5KL&psc=1
https://www.amazon.com/gp/product/B07ZBLLTBC/ref=ox_sc_saved_title_3?smid=A2VHGGOHXF24LJ&psc=1
https://www.amazon.com/gp/product/B01N4G7QCW/ref=ox_sc_saved_title_4?smid=A3HMB6GLG0WJ17&psc=1
https://www.amazon.com/gp/product/B073Y8P6D1/ref=ox_sc_saved_title_5?smid=ALQRVUQVKPAUB&psc=1
https://www.amazon.com/gp/product/B000CQI23Y/ref=ox_sc_saved_title_6?smid=ATVPDKIKX0DER&psc=1
Oh and thanks for the material list that helps a lot.