Ditto on adding weight, however, do you have 4-5 inch I bolts where you attach your planer board cable? The first set that I made didn't have those and I had all sorts of issues with them spinning around in big waves and even pulling the wrong direction or diving on me. Having the longer I bolts on them keeps them from doing that. I also moved the eye a little further back on the board so they would pull harder. I made my latest set out of 1 x 8 x 30 treated pine, so they were already really heavy. I didn't need to add any lead to them.

BTW, if you are looking for some ideas for cheap releases, try using rubber bands with shower curtain rings. If you are having issues with junk fish not being able to break the rubber bands, you can also make some out of the small paper binding clips, with surgical tubing around each side to grip the line. I just put the binding clip on the shower curtain ring, pinch the line in the clip and send it out. Sometimes I will half-hitch a rubber band around my line and just put that into the binder clip. If it doesn't break, you just reel it in and then you can set it back to the exact same depth when you send it back out. Having the rubber bands helps you see when there is junk on the line, as you can see it stretch (like a rod tip).

Why pay 3-5 bucks per release when you can make them for less than a buck and they work just as well.

I made my mast out of PVC pipe that fits snugly over a Traxtech Net Holder mounted in the front. Works great and all the materials cost less than $25 bucks. Most expensive part was the Net holder and track mount.