I'm converting a 60g Marineland cube to a herbie and want to drill for a bulkhead behind the overflow. My return from the pump will be 1" but I will need to reduce down for 3/4" loc-line. Should I put in a 1" bulkhead and reduce after it or put in a 3/4" bulkhead and reduce before the bulkhead? My concern for reducing in the overflow is just space. What fittings will I need? Thanks, I'm new to this.