Using the APC up front is a cost effective tactic throughout the game as it has cheap upgrade costs when compared to the tank.
Approaching Beam Turrets
Unless other factors are at play in a mission don't approach a beam turret head-on. Always attempt to approach them from the side otherwise your rear-markers will get totally burnt.
Decoys
Decoys are good for most of the turrets but don't waste them on straight-line beam firers or the standard fodder.
Repairs
If you upgrade your supply truck you will miss those repairs when they're gone as they could prove to be essential later in the game.
Various Gameplay Tips
Tip 1: Decoys are great for most turrets, but don't waste them on the standard fodder or straight-line beam firers.
Tip 2: Upgrading your supply truck sounds good in theory, but you'll miss those repairs when they're gone.
Tip 3: Popping the APC up front is a viable tactic throughout the game, thanks to its cheap upgrade costs when compare to the tank
The shield's nice, but it's not a requirement for your convoy.
Tip 4: Never approach a beam turret head-on. Unless other factors are at play in a mission, always attempt to approach from the side, or else you'll find your rear-markers burnt to a crisp.