[dddd]

By all means don't add a redundant cable adjuster!

I built up an S-Works this morning and forgot to add an adjuster for the SRAM Red FD, luckily I was able to use noodles to temporarily hold my cable position in the downtube and around up to the FD while I pulled the cable and cut the housing for the adjuster!
I try to get adjusters out of sight, up under the bars but certain not to clatter against anything.

Ferrules are somewhat a personal choice depending on the needs of the particular frame and riding conditions I suppose. Where a cable might exit a ferrule at an angle, the flanged noodles may give smoother operation.
Shielding options may include extended-tip ferrules with or without supplemental seals on the end.
I threw away half of the ferrules that this S-Works frameset came with, mixed in with the bag full of Di2 and wireless plugs, grommets and covers. I used flanged noodles going into the downtube, and also some thicker ones at both ends of the rear brake cable's toptube run.
I added a seal to the end of the noodle/tube running up to the FD, since water and dirt off the rear tire would otherwise go right in.

I made a tool for checking up on whether the cables were crossed inside of the downtube, should have done this years ago.