If I may allay just a little bit of your confusion...
Yes, I know that there is no "outside channel." (and even now I am scourging myself in penance

My point in this whole conversation is that even using a rabbetted feather, and stitching my outseam a little better than an eighth of an inch from the face of the vamp (trying to center my outseam between the vamp leather and the edge of a moderately refined outsole), I am still sometimes cutting the inseam. I wonder how, using a square awl...with the cutting edge perpendicular to the line of inseam stitching...you can possibly avoid cutting the inseam given that you don't inset your inseam at all. And, to compound the problem you're stitching 10spi against four spi.
The reason I ask, is that if I knew how you avoided making "mincemeat" (is that a valid shoemaking term?) of your inseam, maybe I could avoid making "hash" out of mine.

Tight Stitches
DWFII--Member HCC