Try MIRKA GOLD long board paper. I use 40,80 grit paper for fast cutting I call it "rocks on paper". It cuts fast and clean, does not gum up and last a long time. a buddy gave me a sleeve of 3m long board paper and it was terrible. it gummed up and the grit actually started coming off. BUT...I do use 3m brand long board paper in a roll so you peel and stick it to your blocks however long you need. I use the 180 and 400 grit papers for winding down on the primer work and final sand prior to final primer. I use 3m brand "wet or dry" full sheet paper 400 grit for final final wet sand. I don't use the D-A much except for rough cutting.A smooth ,arrow straight finish both in body work and primer is done with blocks. guide coat with cheap "FLAT" black paint-block sand- prime -block -guide coat-block sand etc....Side note..I do not use the scratch putty in a tooth paste tube...over time it shrinks and cracks...USC makes a product called HALFTIME it is creamy, sands great and is non staining...I am not a sales rep...I just found products that work great for me.

1948 Chevrolet 1.5-Ton