Trying to fill the space (read plz)

On average, how big (diameter) should I expect an Autoflower plant to get?
I realize that there are LOTS of factors and am only looking to get a general idea of size, so I have an understanding of how many plants I can fit in my space. I will be using 3-gallon smart pots and MAY train a bit possibly. Tray they will be in is approximately 4' x6'...and entire grow are about 5' x 8'. I utilize high end lights,fans, etc (if applicable) and generally room stays in the low to mid 70s with around 50%-60% humidity (that I am able to adjust, if needed).
PLEASE give any additional advice, if any of this seems wrong. Otherwise, how many plants can fit most likely? Thank you all!
Ps- I do know that good genetics is a foundational key

I have 3 autos at week 7 flowering quite well the space the have in the tent is maybe 14 inch square. But they lay onto the sides of the tent and would for sure fluff out to maybe 20 to 24 inch dia.

Pics from tonight autos on right. Tent is 2x4x6

David Ferguson said:

On average, how big (diameter) should I expect an Autoflower plant to get?
I realize that there are LOTS of factors and am only looking to get a general idea of size, so I have an understanding of how many plants I can fit in my space. I will be using 3-gallon smart pots and MAY train a bit possibly. Tray they will be in is approximately 4' x6'...and entire grow are about 5' x 8'. I utilize high end lights,fans, etc (if applicable) and generally room stays in the low to mid 70s with around 50%-60% humidity (that I am able to adjust, if needed).
PLEASE give any additional advice, if any of this seems wrong. Otherwise, how many plants can fit most likely? Thank you all!
Ps- I do know that good genetics is a foundational key

Click to expand...

And it is dependent on environment, skill of grower . Autos just need enough space for 3 months of average growth til harvest.
You can grow respectable plants in any size ... I grow in 1/3/5 gallons. Any larger and and you are wasting medium that it will not fully utilize . Autos will root as much as it can initially from germ to about 35/40 days before transition. Rooting still happens but plant will slow growth after stretch faze BEFORE actual flower. It will not make more leaf or branches once actual flower happens. Go crazy and defoliant precious leaves during flower can cause shittier yields and possible stalls. Autos hate unnecessary stress , it just wants to make it thru it’s short life without drama. Autos do not need complicated feeds or manhandling.

Quality of light is a BIG FACTOR in good / great autoflower results. Underpowered gear or cheap alternatives will show in end.
You can grow monsters in 5 gallon DWC / HEMPY STYLE. Most soil grows use 3 gallon sizes. There are super auto strains around too .
Mephisto is the leader of refined autoflowers and make dank ass weed , but their many other good breeders too.

Chart will give you a rough idea of plant size.