I have been reading a lot on the other site about affinity points for edge points, and I would like to know if eight is a safe affinity to be at in order to get invoker edges? Maybe a help file that shows the affinity needed for that particular edge?

Straight from the other site.

Scalding geyser and Chilling Geyser. What do they actually do? I understand what chilling and scalding means, but is it as if you're doing two spells at the same time for double damage? You fight a felar and have scalding geyser, is it going to be struck with a double vuln because of geyser=water/Drowning and it's scalding geyser, so does it strike with a heat the felar is vuln to? I'm like the other one and wondering what it actually does, or if it's just added damage.

Thanks in advance.

I believe 7 is sufficient in order to get those edges.