This is what I have done from time to time. First you have to let the idea of dry feet go by the way side cause your boots will leak.
Take out the felt or wool sole liner in the boot. Find some dry wall screws that are about 3/8" thicker than the sole of you boot. Screw them through the sole from the inside. Wha La you have a pair of caulks.
First screw them in from the outside through a lug in the sole for better support mark to hole on the inside then run the screw down from the inside using the first hole like a marker and poilet hole type deal. Then get some shoe goo or rtv type stuff and smear it on the inside and smooth it then goober it around the screws on the outside. This will help keep water out and help strengthen the screw in place. If less than 3/8" will work for you go as short as possible it will put less strain on the screw and they won't pull or bend as bad and will last longer.
This takes time but it does work. Done it quite afew times when the kids or wife needed something I though was more important than new boots which is just about anything for them.
Oh ya if anyone does see ya wearing these homemade hobb nails their gonna laugh at ya. Just look at them and say mine only cost me $2 how much did yours cost. They find out your only cost the amount of the screws and they will be asking how you did it and if you will show them how.
Hope this will help ya
Owl