Switching GC / picking different one from before

[Alhanelem]

Does it matter if I pick a different GC from what I started with and switch to the original one later or start with my original and switch to something else- Do I lose everything from the original grand company either way? or would I have my rank again upon switching to my original company in the latter case?

(it was stated if you rejoin your original company you keep your rank and seals, while if you do not, you keep nothing. But what isn't clear is if that's permanent, or if you get your previous rank if you switch to that company later.)

To be clear, what I want to know is this:

If I choose a different company than I had in 1.0, *then switch to my original later*, will I have the rank I had before, or does it go up in smoke the moment I don't choose the same one I had before?