I like to add another DLS Iridium 6.2 front and power both with 2 DLS TA2 amp. but I don't know If my Helix A4 is bether than TA2 or not.
for sub stage 4 DLS 12 Iridium and 4 DLS A6. or at least 2 of each.
x2
you need a passive cross over.
but you can run each set on 2 chanell of your amp.
or you can use your mid's on bridge mode.
and use the tweeters on 2 chanel seperatly.