i do a combination of matchup/team situations and studs upgrades (although in my league we are lucky if there 3 trades all year so it doesnt mean a whole lot)...i think the depth for injury concerns is a good safe bet but depends more on who u are dealing with....certain guys make you nervous (ap , mcfadden,nicks) come to mind off the bat) where i think you should either try to land their rb handcuff or have a backup plan.....
remember also there seems to be alot of end of the year guys who step up out of nowhere due to injuries, teams in the playoffs and resting, teams out of the playoffs and trying out different things