I wound'nt worry about boards flipping unless your fishing in 4' to 5' swells or more.Besides that if you put weight on them I would think that will make them sit lower in the water and make them harder to be seen by other boaters.

 

Yep weight the outter back edge does help only if needed will help keep em from hopin.Tried a t shaped hydrofoil on back in spring worked fine.Good luck.

 

When boards first came out - some of the early designs tended to flip over easily. They flipped in towards the boat - not end over end.
Not sure who came up with the idea but adding a 16 or 20 oz sinker on a one foot heavy mono dropper from the back outside board washer seemed to help. Guess it acts like the keel weight on a sailboat.

Most of the newer designs run fine in 2-3 foot waves.

 

Before I started fooling with weights, I would try to fine tune the eyehole position.....my experience has been that if your boards are "jumpy" then the eyehole is too far back......move it forward an inch and go test run in some chop.
If you must fool with a weight, a 20 oz ball sinker off the rear outside edge will do the trick, but a better method would be to get a strip of lead and screw it to the bottom of the outside board.