I do this:

1) unscrew the eyes about a turn

2) Pry the eyes open with a screwdriver blade.

3) Put a swivel into the eye, crimp it closed, and screw it back in. I use the 75 lb rated swivel, forget what size that is.

4) Clamp a siwash hook onto the swivel. I use 1/0 for K14's, 2/0 for k15's, and 3/0 for K16's. Some folks use larger. I haven't had problems with these.

5) Bend the point of the hook offset about 10 degrees. I do the back hook one way and the front hook the other.

This works with K14's through 16's. I tried it with a K13 earlier tonight, and it didn't work. The hookkeeppers on those appear to not be screw eyes, and to be cast into the plug. May have to use trebles on the Columbia.