Unglued in tank should be fine. The bulkhead is schedule 80, so soft. If you stick your regular white schedule 40 in nice and deep/snug will be fine. You could glue it too
Good point from Reef Trends,
Yes, Durso style will quiet it. Stockman style more so, and a bit adjustable. You could do Herbie overflow style, with the 2 pipes you have, for dead silent. Or drill another bulkhead and do Beananimal style and have silence and another drain for emergency
All these styles, including the one you have pictured, the water level will fluctuate depending on gph from pump, and amount of restriction on drain. So a lil more wiggle room between regular drain or drains, and emergency drain is a good idea.