I only have a three day batch every year or so. This does the job and and avoids lye burns to the tongue. The trick to taste testing cured bars is to just touch the tip of the tongue to the bar or, better still, get a smear off the bar with your finger and touch the tip of the tongue to that finger. Lye burns in the mouth are NO fun. I have made several painful mistakes that way.
Polyethylene pails in a double boiler work well for making soap.
Even an amature soap maker should use some kind of scale to weigh the lye rather than try to make volume measurements. Grapefruit seed oil is an antioxidant, germistat and stabilizer. I use 10 times this much to make germicidal soap. I use Dixon Crucibles Colorart Powder Tempra for color with good results for most colors. These are children's tempra paint colors mixed with 50 grams of shortening and whipped into a roux, then adding this at trace.