well if you plan sticking with peat, your gonna need lime to help balance out the acidity just to get started. as you said most will tell you get rid of the fert spikes
but i know people who use them all the time, cant say their grows are any better for it. not sure what the ratios are but it would surprise me if they were suited for herb.
if i was you id do a quik search for soil mixes...actually i think there is forum specifically for that.