Oops,
I missed this.
I'd actually be surprised if you went PURE SD and male that you'd wind up with a 12 footer. I'd say its rather unlikely.
My animal is predominantly dwarf, and SD with 18% mainland in the mix.
He's a bit over 3 years old and 8-9 feet. He's fairly topped off.
Had I waited and contacted Reach Out Reptiles, Garrett would have been able to set me up with an even smaller animal.
Holding off for now is a wise decision. Your living quarters are far more important!