In my layout the bulkhead nuts are impossible for a wrench and not even that easy for fingers. As the nuts should only be hand tight, made up some "sockets" for 1" and 2" bulkheads using pieces of aluminum and PVC pipe that would fit over the threaded part of the bulkhead, then milled out for the nut. Added some abrasive tape for grip.
Do have to say worked perfect for hand tightening and if wanted tighter could put a pipe wrench on them or drill holes for a bar.
