The C-12 tube position is virtually Identical to a real C-12 it was my intention to emulate the original circuit as close as possible on the Apex mic not to make "so called" improvements.
As for the 251 in this case the grid wire is similar length to the C12 which I don't feel effects the sound in any negative way also I left space at the top of the board for those who wish to incorporate relies for pattern switching. The C12 and 251 do have different noise floor but this is due to the Biasing differences rather then the length of the capsule to grid wires. I hope it's clear now that all design choices were made intentionally 8)
As for the 251 in this case the grid wire is similar length to the C12 which I don't feel effects the sound in any negative way also I left space at the top of the board for those who wish to incorporate relies for pattern switching. The C12 and 251 do have different noise floor but this is due to the Biasing differences rather then the length of the capsule to grid wires. I hope it's clear now that all design choices were made intentionally 8)