Here's a nude in the woods on a 10x12 done with a Dallmeyer 3A. You can see the vignetting beginning in the corners and it would only be worse (or better, depending on your outlook) on an 11x14 plate.

10"x12" Ruby Ambrotype

The 3A and 18" Verito are huge lenses and quite heavy. You may wish to think about some sort of auxilary support for them on your Korona. Here's a 3A on a 9" board on my 11x14 Burke and James: