I was thinking of 8'ers but usally where the pigs are here it's open enough that 16' would still be easy to use. It also looks like you used two sets of hog panels, how tall is the trap from top to bottom?
About 44" to the top bar. Then I had barbed wire above that. That holds most pigs. But a couple of years ago I trapped a rank boar (twice) and he just crawled over the top. So I added some more wire panel to the top. If I was building them again, I would make it 60" or so ... and leave the wire extending over that ... with barbs protruding.
Also, I am changing out the gate. I have ordered an "Iron Curtain" gate from Jay Dore that I plan to use with these panels.