I use dedicated 5x4 sheet film holders - picked mine up for a song used for about $10 for 5.
To agitate, I use a "dip and dunk" style - place sheet film on holder into dev and every agitation lift out, angle down and place back in; repeat but angle the opposite corner down and place back into dev.
From memory, I think I did this 4 times per minute: lift, angle corner closest to me, dunk; lift angle corner farthest from me, dunk.
Bought the containers from Target or KMart from memory (could probably even get at a Woolworths), they included lids. I just took one of my holders along to make sure they fitted - hang on each side perfectly with enough room at the bottom so that it doesn't touch. I can process up to 5 sheets at any one time using this method.
Total cost: $15.00