If you are having bad luck with toothpicks, you may try turkey skewers???

Well I may try the toothpick thing with the other avocado, The seed is much
smaller than the one in the pot. It will probably be so small I am wondering if
I just couldn't find a metal screw, I'd only need one an inch or so long. Wait
till it breaks in half then try to screw it back together.
Or just use a nail to pound my holes for the toothpicks just to make sure they
are deeper than last time. I'm sure one of those tiny nails used for picture
frames may work.I just have to be careful not to shatter the seed when I pound
them in.
Steve