Tire and wheel size

[Budweis]

well i finally decided im going to give up on finding drums for my 70 c20 3/4 ton and convert it over to disc . i figured while im at it im going to add a 4" lift and some new wheels and mudders. my question is do i go with 15" wheels or 16" or 16.5" like i currently have? and what depth of rims? i was thinking 10" as i wanted some pretty meaty tires.but i also dont want rub problems so i figured id get some suggestions and also any advice on offsets or if someone has same setup maybe you could recommend some part numbers also does anyone know what size mudders i could fit on my truck with this setup? any suggestions appreciatied. oh yeah also while im at it do i want 52 inch springs for the back or 56 and what are the differences? or 4 inch blocks for the back? sorry for the load of questions but really wanted to start ordering parts and getting on this.