Grounbaits & oils including some pop up questions

Just bought some worm additive to put into my groundbait with chopped worm & caster for perch. How much would you reccomend putting into the groundbait? Is there a suitable groundbait for perch?

While I am on the subject of additives I am going to try boosting my sea deadbaits with Sardine Oil. Do you inject it into the skin of the deadbait, the vent or elsewhere? agin how much do you syringe in.

Finally has anyone had any success with air injected lobs & pop up deadbaits in stillwater predator fishing?

CJ