going 60g sump, 180g tank, wondering what size plumbing and how many holes. I was thinking 2 intake and 2 returns 1.5" bulkheads. Any advice would be great!
Your initial thoughts are exactly what I was going to recommend. Except your return lines don't need to be as big; (2) 1" lines would be perfect because you want some velocity through your discharge lines for water flow into display