I "think" I'm feeding the stock slow enough, but the blade still
bends and the cut starts to wander. Any suggestions?

First question I have for you is what kind of blade are you using? As far as
the "right" tension, it should sound like a high "C"....think of it as tuning
the strings on a guitar. 1/8" side to side movement sounds like an awful lot
to me although I never measure it. My first thought is that your blade isn't
tensioned enough, not enough tension makes it virtually impossible to follow a
line. It's something you get a feel for with experience. Just takes lots of
practice, I've made a lot of nice scroll sawn firewood while learning.

Hope this helps,

Kevin Daly
http://hometown.aol.com/page1.html