Seeking Advice on Drawing Heads

Head studies Sept 2024 by Katt Quiet

These studies each took 15 to 25 minutes. I used pen, because I'm trying to overcome my habit of erasing constantly. However, these studies are from the 360 degree tool and portray the same model, but my initial proportions (when I don't erase and correct them) are so sloppy that these look like different people to me.

My question is, would a combination of head anatomy and drawabox and loomis studies help me, or is there something else I should be studying? Or should I keep using an eraser and focus on only head proportions for awhile?

Any suggestions or advice will be greatly appreciated. Thanks!

@run 3 it is better for me to focus on head anatomy in addition to drawabox and loomis

Adding to chukio's advice. Drawabox is more directed to drawing boxes from an angle. The 250 boxes challenge personally game me a worse understanding on how perspective works unlike when I was at box n 180, but take it more as a personal advise. Loomis is a pretty advanced resource so unless you have a more technical perspective on drawing I think that might be for you.