I'm in a very similiar boat.. I have Jackson and Tolbert as well..
Tolbert the past two games has only rushed the ball 5 times, yet has had 2 TD's. Ryan matthews has only had 1 TD over his past 35 carries. Tolbert is definitely there goal line back.. Houston's Run Defense is not that great.
Jackson is their primary back but the Packers just dont run it. I'm had him for awhile now and he only gets me about 6-8 points a week. Not to bad, but never a breakout performance. The packers spread the ball all around, much like the Saints. Cowboys are probably not going to come out and play hard after Rodgers throws 2 or 3 Tds in the first half (haha my guess) so then the packers will run the ball with jackson...
I doubt he gets a TD though.
Basically the question is, take a shot with Tolberts 3 carries and pray for a TD (7 points) or (.2) or take Jacksons 4-8 point week.
Jackson is probably more reliable but wont have a high scoring week.. I am going with him.. Tolbert may score twice for at least 12 points but I dont see high risk high reward .