(you can do this without drawing the rough nose, just click on the right spot) And usually when I draw the nose out of peg, I can better see the arc for the ear for exemple, so I use my script again and I out of peg the ear directly cause it takes into account the already set out of pegs (you can do that for each part if you want to be precise, beginning with the most obvious reference points for your spacing like the clavicle then the chin, then the inside face details). I think it's far easier to visualise where the inbetween of one point will be (for example the nose) and just click on this spot, drawn or not, then on the nose on the two surrounding images same for scale and rotate with a second reference point.
But all you need is to use your current drawing as the "guide" to move the out of peg drawing, not your already existing drawings, it doesn't take much more time (in harmony I also work the same way as in tvp, I don't move current drawing usually). Also if you want to calculate any position from the position of your out of peg, you would still have the problem of modifying your drawing that is not in place. But in tvp you have to align lighttable drawings on the current current image, not the other way around. I understand what you mean, with paper you line up your two drawing and put your current sheet in the middle where you want it. Sometimes I don't draw my inbetweens, I just click with my tool where i want my inbetween to be then on the two lighttable images and everything is at the right spot. Yeah my tool is always used on a "roughed out inbetween" (even just a point, or two points if you rotate/scale).