Tips on marking outseam lines?

I'd really appreciate any tips on how folks go about marking stitch lines for outseaming by hand. Do you scribe a line a set distance from the inner seam stitches? From the edge of the welt? Just eyeball it?

I haven't been happy with the outer seams on a couple pairs lately. I've been marking a line and then using an overstitch wheel to get straight lines and consistent spacing, but the distance from the upper with the shoes on feet hasn't been pleasing or consistent, especially around toes. Looking straight down, sometimes the lines run right up to the uppers, and sometimes they veer away.

In case the details matter, I've been using a square awl and saddle stitching. I'm happy with the shape of the holes on the top and the positions of the exit holes on the bottom, as well as the look of the stitching. For now, the only problem I'm seeing is where the stitch lines run relative to the uppers.

I really appreciate the time folks to share tips here. I'm just a beginner, but I'm doing what I can to pay it forward!