we get alot of questions here about helmet sizes, qualities etc. many of us that have been around a bit have answered the same questons many times. so, i thought i'd take the time and my most recent helmet related post and make a brief "tutorial" on helmet sizing and quality.
if you go to the trading forum, you'll see gypyboy is doing mando helmets for about 80.00. just have to wait for the next run. also, icktan westdar is preping runs of a custom mando-commando helmet for about the same cost. if you want a fett style, sgt. fang over at tdh has cleaned up the old "mystery helmet" and is making continuos orders on those for about 100.00
if it's a funds issue, i would recommend you save a bit longer and invest in th better helmet to start with( a rubies 1 piece jango will cost you 60.00-80.00 shipped). many of us "old timers" here have made the mistake of continuos upgrades to our helmets.... 3-5 helmets, hundreds of dollars and tons of time later we ended up with marrow suns, boba makers, gypsyboys, sgt. fangs etc. i personally am on my 5th helmet, although my 2nd was a keeper it was retired. i currently have a gypsyboy boba i modded and i love it. it's full movie sized and well built.
just my personal opinion here however, most will agree...
boba 1 piece boba: good for young kids only
jango 1 and 2 piece: good for petite to medium women, children and petite men
don post 95-96: good for med or larger women and medium framed men
if you dont fall into on of those, you'll need a movie sized helmet which would be gypsyboy, sgt. fang, boba maker or the wizard of flight templates (for those who wish to make there own).
if you are especially large framed, there is 1 maker of jango fett helmets that makes a helmet that's about 10% larger than the 1:1 helmets. i don't know the maker off hand however, i have a friend with one and i can obtain that info for you if you pm me.
another thing to consider is that the helmet should look slightly large compared to your body if you put it on out of armor. wearing the armor adds alot of size to your frame. so, if you get a helmet that looks proportionat to your body out of armor, youll look likea pellet head in armor. while you shouldnt look like a funko bobblehead with it on out of armor, you should look like you're getting there.
Here is a side x side comparison of buckets and sizes:
left to right...
rubies 1 piece boba, rubies 1 piece jango, rubies 2 piece jango, don post 95, gypsyboy (the one on the end is a rohlan dyre type crusader era helmet)

Courtosey of Taglar Dressk. Gypsyboy vrs. Rubies 1 piece Jango Fett.




to give you an idea of how the helmet looks in relation to the armor for accurate sizing, here's some pix pf me in my armor:
1st helmet, rubies 1 piece. my chin hangs out the bottom and the helmet looks small compared to the armor

3rd helmet, don post 95. helmet size is a bit better but, still small compared to the armor. my chin doesn't hang out anymore but, my face is smooshed against the visor and to get the front to cover the chin, the helmet is tilted so far forward, that the back of my neck is exposed

current helmet, gypsyboy 1:1 movie accurate size. proper fit and proper size ratio to armor

here is a pic of my oldest son in a rubies 1 piece (9 years old)

my youngest son in a rubies jango 1 piece (6 years old)

my gf's son in a rubies 2 piece (7 years old)

my brother in a rubies 1 piece boba, notice how small the helmet/head looks compared to his body (dont mind the rubbish plates they're way to small as well!) his head was lierally smashed into that helmet!

my brother in his upgraded armor with (my old) don post 95 helmet. size ratio corrected. he's a medium build adult 5'10 180lbs.

At the end of the day, you can get a quality resin helmet for only a bit more than a latex helmet that will warp with heat. a quality fiberglass helmet will cost nearly double that of a resin helmet and a really nice cold cost helmet made wih aluminum powder (so you can buff it silver for your base coat) can cost up to and over 300.00. for most costumers, especially customs, i would recommend the resin 1:1 helmets.
i hope this helps with your helmet sizing options!