Also as I have thought about this, the "who gets immunity" pick won't be available for the first week as we (probably) won't know what tribes they have. And then I think perhaps for the rest of the first half of the season it should be "which tribe goes to TC", and then changing to "who gets immunity" after the merge.
If Ten runs this three eps a week, it's too much hassle for everyone to be sending picks every day -not to mention a logistical nightmare for me - so I hope you'll just run with picking three eps in one go. If your picks for the Mon or Tue get voted out on Sunday that's just too bad. No chance to change your mind. And if there are two eps instead of three in any week your third picks are void, they won't carry over to the next episode.