First off, these are great! You can definitely recognize you're drawing real people and get some idea of their race. They way you draw the eyes, is very expressive and detailed. I'm not too good at this stuff myself but from what I know I have struggled with, is similar to what you seem to be struggling with too. I would always take my time with the outline and shape it out as I was taught. Then, when it came to rendering out the final form, I would use the outline, but if things didn't look right to me I would just change it. I think you're doing this too, you gotta remember though, if one section of the outline is off, everything else is measured off of that "wrong" or iffy area. So I recommend figuring out what is wrong with the outline, or in this case, the loomis head you're drawing. Things I noticed is that the inner circle is always 1/3 from the bottom half of the outer circle and 2/3 from the top half of the outer. Then it stretches and moves depending on where the head is facing. Here, I drew up some stuff to better show you! (it was really quick, so forgive the sloppiness) I hope this helps!