starting to build my own sound system

hi guys im thinking to start to build a custom sound system for dub,steppas and need some advise

my idea is to build a 4 way system with
four 21 inch sub scoop bins
two 21 inch kick scoop bins
four 18 inch mid high horns
and two times 4 tweeter boxes (Icosagonal)

i would like to run with a custom built pre amp with internal crosover and 10 band graphic eq (ENFORCER JTS or dubsonic dub master)

but i would like to have the design clear before buying any components

my question is i cant find plans for a 20 inch super scooper for the 4 subs and 2 kick bins
and not sure what the best design is for the four 18 inch horns

and when it comes to buying drivers and amps i am completely lost as their are so many

am i going in the right direction

thanks in advance

looking for some thing like the picture