I generally like to use the Drone first because you can activate it whereever and whenever you want, i.e. mid-air when dropping into a boss arena. It also seems like there’s a shorter delay until you can spawn your clone after activating your Drone than the other way around.
The Clone I usually like to place pretty much in the middle of an engagement, right into the enemies face at which point I then usually try to flank around the group or retreat back a bit.
I mostly use the swap for one of two things:
1: Healing up the Clone with Quick Breather
2: Escaping situations where I am getting surrounded or rushed down
There’s a number of good weapons for the Clone. He’s fairly accurate with snipers (and does actively try to aim for crits), however since he doesn’t have recoil compensation and immediately stops shooting when he gets off-target, his rate of fire can suffer a bit.
The Clone is best with weapons that either have little to no recoil or weapons like the Hellwalker that reload after every shot anyways. On the other hand you might want to give him weapons that do great damage but wouldn’t normally be considered ammo efficient, like the Sandhawk.
The Clone is also solid with Rocket Launchers in general, but in that case you need to be careful that he doesn’t get rushed, otherwise he might kill himself with his own splash (or just use a shock weapon with a Transformer because the Clone doesn’t get bonus elements, anyways).