to double them up or not to double them up

[dickkemp]

PokerStars Game #13343064068: Tournament #67693199, $20+$2 Hold'em No Limit - Level V (75/150) - 2007/11/19 - 17:16:04 (ET)
Table '67693199 1' 9-max Seat #8 is the button
Seat 2: dickkemp (2420 in chips)
Seat 3: Bmore Dave (685 in chips)
Seat 4: djmaxtinelli (3555 in chips)
Seat 6: Fiddy23 (5750 in chips)
Seat 8: Rifle_Maan (1090 in chips)
dickkemp: posts small blind 75
Bmore Dave: posts big blind 150
*** HOLE CARDS ***
Dealt to dickkemp [5d 3c]
djmaxtinelli: folds
Fiddy23: folds
Rifle_Maan: folds
dickkemp: folds
Bmore Dave collected 150 from pot
Bmore Dave: doesn't show hand

my question is how little does the big blind stack have to be for this to be auto shove and how does my stack size come into calculations. how big does my hand have to be to shove into a stack larger than this one? i guess more the question is how do you decide whether to fold or shove in the small vs big situation like this?