I have a PC that's interested in crafting his own foci, but we can't figure out how to do it. We've got the basics down, but can't determine how many reagents he will need to use.
Street Magic's very clear about how many you need for fetishes, talismans, and ritual materials, but says absolutely nothing about how many you need for foci of any variety.
So question 1: How many refined/radical reagents do you need to make a focus? (Note, I'm not asking how many you need to get the bonus on the Enchanting roll)
Question 2: What's the difference between reagents of the same variety? More specifically, why would anyone use venom, valued at 600 per unit, over blood, valued at 50 per unit?