swill.... you have to specify "custom polygons" or yes, it will draw it in a square/rectangle
http://builder-docs.swillkb.com/features/#custom-polygons- you could do it in another program as well.
- use swill to get the plate files, then design the outer bezel in another program
- make sure you get kerf, etc. specifics from whatever vendor you end up choosing, as this usually needs adjusted in the file.
if you're adding a F-row, it won't fit in the normal ergodox case
if you're not comfortable designing a pcb, don't. either have someone else design it for you or handwire it.
handwiring is not that hard and could pretty much guarantee a working board (as long as you don't have any issues with the soldering).
it's a lot easier to mess up a pcb than it is to mess up a handwired board.
the ergodox is a unique board as the pcbs use an i/o expander instead of dual controllers like most other simple split boards. (there are way more split boards that use 2 controllers than ones that use i/o expanders). not that it can't be done. but is not as straight forward as using 2 controllers.
so, component choice.... no, shouldn't change. AS LONG AS you have extra pins to work with to add your extra rows.