I'm doing something similar.. I was just using black oil sunflower seeds with great success ( 7 day colonisation time)but the last 50 lbs bag I got wasn't black oil and(still sunflower)the seeds were horrible and my jars kept failing.. so this time I got a bag of wild bird seed mix.. I'm trying two teks with it.. one was the no failure w.b.s. tek where they removed all of the sunflower seed and no 12/24 soak time.. I was under the impression that soak time allowed endospores to partially germinate so they are easily killed during p.c.ing... ? Anyway I'm trying it,, first time I've done w.b.s. in your opinion which is better,, boiling the seed in diluted coffee ( so the coffee penetrates the seed)or just using grounds and mixing it with the seed during jarring?