Early Wk. 4, 6-pt. Teaser possibilities

I know that teasers aren't seen as sound bets around here (with some dissent), but SGB offers a 3-team, 6-point teaser at 2-1, which I've calculated to be pretty damn good. So I like to play it.

I know the 3-to-7s are key here, and at first glance, I like the look of:

Sea @ Was: Sea +2 to +8
GB @ Car: Car -7.5 to -1.5
SF @ Ari: SF +2.5 to +8.5

Also, though it's not a 3-to-7, I'm a little interested in

Ind @ Ten: Ind -6.5 to -0.5

Given the Colts's habit of winning, but winning narrowly, this one seemed to make sense too.

I guess I'm looking for thoughts both on the specific games, and whether this kind of betting is even worthwhile in the first place.