Bless my loving wife!

[e46er]

ok say you drill all the holes the same size......

i personally would go dual overflow as its semmetric single overflows look out of place but thats me

you drill 2 holes same size for a single overflow

drill bit 16 bux shipping 7 bucks tax 3 bux =26
2 bulkheads $16 and thats a pretty good price
your overflow piping + fittings $20 and thats pretty good PVC isnt cheep

i had 3 pcs of glass cut for tank covers from a friend for 25 bucks but he said anyone else $45
so say you get the glass cut for $25

your total is now $87 for a single overflow and thats with good prices plus the labour you put in plus the fact if it cracks your out the cost of a new 90 tank $250 plus you give up a warrenty on it(he has one becuase he bought both the tank and stand combo)

im a big DIY guy nothing has been done to my car out of warrenty my entire tank was set up plumbed stand canopy sump built by me. but there is a line between doing it yourself and what your risking ie a $250 tank to save $13 POSSIBILY

that being said. grab 2 or 3 size drill bits and drill 10 holes in the back wall and have an awesome Closed loop (powerheads are ugly too)

this is my opinion and i havent been into SW very long tanke it with a grain of salt but im sure others agree with me