You probably don't want to use the benzotriazole in the emulsion - I think tetraazaindene (TAZ) or phenyl-5-mercaptotetrazole (PMT) are more appropriate. PE will most certainly follow with suggestions on how much to use, and it will be based on the amount of silver in the emulsion - on the order of milligrams per mole of silver.

I've bought TAZ and PMT from the Photographers Formulary, already prepared into solution. You need to ask them about it, as I don't think they have it listed online anywhere. It was pretty inexpensive.

If you have benzotriazole, have you tried adding it to your developer to reduce fogging?