Building a new 24 inch cube. Want to get input on adding one or two gyres or should just use a traditional pump? Any experiences are greatly appreciated.
A properly-sized Gyre would be a solid solution for your setup. It keeps things simple; with a properly sized and located Gyre in combination with a well-thought-out aquascape you will be able to keep food, particulate, and detritus suspended (and ultimately transported to filtration).
I'm not a fan of the Gyre pumps (I'm lazy so I use Vortechs as maintenance is very quick and easy for these), but if I was going to use them I would go with the following layout:
2 x same-sized, controllable pumps (timers could also be used in place of controllers if you only have/want a non-controller pump)
Each placed near the top of the aquarium, facing each other (one on left panel, and one on right panel)
Have them pushing flow opposite one-another (while one is running, the other is low-speed or off).
A while back BRS did some flow videos and used a similar setup using Gyres - would be worth a watch.