Don’t get me wrong, I love OG EB’s but If you build your own you can get a 12 Gal tote with the same dimensions as a 10 gallon. They are just a bit taller.
You should be able to get 3 homemade 12 gal in a 3x3 with plenty of room to operate.
Not only that but you can customize the water Res to whatever size you would like.
You can move around a 12 gal much easier than an EB if needed also.
If you install the overflow with a tube as pictured below you can also drain water out pretty easily if you want to make it lighter to move.
I can tell you that it seems that every time I build a new SIP I am customizing the design to my needs. I only have a few SIP’s that are built the same all others are just a little improved upon each other.
A 12 Sip will hold plenty of living soil to grow a plant large enough to fill that 3x3. Plus if you purchase them in bulk you can start a DIY worm bin going too 
And Yes! I have a thing for DIY Sip’s…
I have not had the pleasure to grow in a EB Junior but I can tell you the 7.5 Gal DIY sip takes up way less real estate and will produce some pretty decent size plants (Not monsters).
This little girl measured 3 ft tall from the top of the SIP to the top of the plant. I loaded it up and have watered it only since it was put into this 7.5 from a small plant.
She is in flower now and I have only been feeding her Kitchen scraps. My son calls them worm smoothies. And yes, I do pick and choose what goes into the worm smoothies. I save all kitchen scraps in separate containers depending on their NPK. I did feed her some Kelp in the last worm smoothie also. As you can tell by the word Smoothie I do put the kitchen scraps in the food processor. The worms tear it up. Oh, I do spread a little grow kashi love every know and then.
Just trying to give some more options for the DIY crowd.
Oh! and I am with @minitiger on not getting snipped.
Just my personal opinion though!
On the rest of It I will stick to never
this…