Hi Daniel, To answer your 1st question about using shrimp as bait for coon etc. I used to have a friend years ago that would save the uneaten tails and just little parts of shrimp.He would put them in zip lock bags and store in his freezer.I saved mine too and would stop by and get his and store in my freezer and have a decent supply of them before season.During season I would unthaw a bag or 2 at a time and use as bait for coon and they did work well. I have used shrimp that had went bad and were just slightly tainted but did not smell horrible.And they seemed to work also. Usually I would use a shot or squirt if fish oil or salmon oil along with the shrimp or what ever kind of bait I'm using. Sometimes rather than fish oil I might use a shot of sweet sour type coon lure.
About your 2nd question on the amount of Shellfish oil to mix in to your melted jars worth of petro jelly or lard ? I don't know for sure but I would think with the amount of the lure base being a jar size of petro jelly I would think that one oz of Shellfish oil mixed in would make for a pretty strong smelling smear type lure. I'm not sure if Paul sells shellfish oil or not.But I do know I have used Dobbins Salmon oil as far back as when his Father Charlie was alive. And that Salmon oil has always been strong and has worked well. I also used to use Mike Marsyada's shellfish oil,which was more clear looking rather than yellow,and it was Strong. Just a couple ideas for ya. I think I would start with 1 oz or a partial oz to your petro or lard.Let it cool and settle and see what it smells like.If you feel it needs more then remelt and add more.One thing a lure maker used to say about smear baits is if after several days it seems to loose it's smell then just re smear over to like open it back up again.And that way you don't even need to add more.You can just continue to "reopen" it
so to speak.