Which .tib file do I choose?

[Peter 021108]

I am still confused. Perhaps someone can help me croos the t's and dot the i's, please. I have a full backup file created day 1. One day 2, I manually do an incremental b/u selecting that full backup file from day 1. On day 3, to make an increm b/u, I should select the file from day 2. I'm assuming that's correct, right?
Now, to create a task to b/u every weekI would first do a full b/u. In creating the task, I would selct this first full b/u file as no others exist at that time. Therefore, after 4 weeks, I have now 4 increm. b/u based on the first full, rather than on the most recent increm. file. Doesn't that make all subsequent files bigger and bigger all the time?

[MudCrab]

Incrementals are based on the previous Full and all previous Incrementals in the backup set. The new Incremental backups can be smaller or larger than previous Incrementals as only new changes are saved.

Differentials are based on the Full backup only. Differentials will normally get larger with each backup. However, if you delete files that were in a previous Differential backup and not in the Full backup, the image may get smaller.

When selecting a backup, just select either the Full or any Incrementals or Differentials in the set. TI knows they go together and will add to the end.