I finally worked up the courage to begin assembling the pack, beginning with the straps, as per the instructions. I didn’t get very far–only put the thumb and tube loops on the strap linings. Baby steps, baby steps.
Mostly I’ve just been fiddling with the sewing machine. I was having some trouble with the ripstop, as the stitches were not uniform. I assume this is caused either by slipping or sticking of the fabric, probably the latter as the stitches sometimes appear to be smaller than they should be.
I read somewhere that a walking foot or teflon foot would help. A walking foot at John Lewis was £40, but the person helping me suggested that I just put some tissue paper underneath, so I might give that a shot. The cordura seems to go through the machine without a problem, though.