Thanks @beowulf! I think she’s pretty adorable too, not that I’m biased or anything.
I know how you feel. I’m the opposite, if it’s on the tightest hole I don’t think it fits. My pet peeve is halters that are way too loose, so I error on the side of too small rather than too big! I thought about ordering a replacement crown in cob so it would have a bit more space, but decided if it really bothered me I could use the crown from her old halter. It never bugged me too much so I kept the new one, and now that it’s stretched we’re on the 2nd and 3rd holes on each side.
I just re-read your OP and saw you’re looking to fit large ponies/Arabs. My girl is 14.2 and 1/4 Arab and has what I would guess is a typical Arab head - big jowl and small nose, if that helps!