YASoob ,
hey been a min. sorry for slow reply .
i started w/ only 1-1000w. n expanded later . thus the 2- 6in. vortex fans verses the 1-8in. / as far as your filter , 6in. vortex will be fine .

i have a couple sharp turns in my duct work . i have no light leaks w/ galvanized ductwork and it doesn't obstruct flow like the accordian foil type duct.

also doco is right , plan 1= bad cause you'll be pulling carbon dust through your lights n gettin em all dirty .

i'd go w/ the 8in. on lights -n- 6 in. on filter .
my rooms not to loud w/ 3 blowers going , but i have a fan speed controller on the 2-6in. blowers -n- my stuffs in my basement anyways .
peace
crispi :thumbsup: