I am getting ready to brew a big Russian Imperial Stout, using WLP001. I have 1 vile on hand and don't really want to spend the another $7 or more on more viles. So, my choices are make a starter, (first time for that) or use in instead of the packet of dry that came in my Porter kit and then pitch the RIS right on the yeast cake from the Porter. Which would be my best option?