Missions & Complexes

There are several techniques. One is to drop a can with one unit of some sort of trash (or maybe one hybrid charge, missile, or ammo round), orbit that to keep up your transversal, and deploy sentries close by. Another technique is to catch aggro, drop the drones, and then kite the rats - drag them into the sentries' optimal range.

It's dependent on the type of drones you're using, which is dependent on the type of rats you're shooting at - if you're up against Guristas or Serpentis, you'll want to throw kinetic damage, which means Wardens with an optimal range of 50km (T1)/60km (T2), so you can just drop the drones, stay fairly close while maintaining high transversal, and blast away. If you're up against ships vulnerable to thermal damage, that means Gardes, which carry more punch but have much shorter ranges, so you'd have to kite them into range.

In an Ishtar, you typically drop the sentries and then haul off and get into optimal range for your guns while speed tanking the enemy. When the battle is over, you run back and grab the sentries. The Ishtar is fast enough that there's not much time lost in the transit to pick up the sentries. Of course, with the new AI changes on the way, leaving the sentries may result in the loss of some drones because you won't be there to pick them up, so I expect we will see more folks just orbiting the sentries even in an Ishtar.

Right now I use a sentry domi and I literally just drop the sentries and sit there with my Domi tanking the incoming damage. The Domi has enough tank when properly fitted that it doesn't even need to move to mitigate incoming missile dps. Just be sure to focus the sentries on the frigates first as soon as they get near the optimal range of whatever sentry you're using (I use warden IIs and garde IIs which have, respectively, about 120k and 50k optimal ranges with my skills/fit). The sentries will pop the frigs before they get close. Then switch to cruisers, then BCs, and then finally the BSs. If a frig or cruiser gets through and orbits you closer than your gardes can effectively hit, just ignore them and kill off the remaining large ships. Then you can haul the sentries in, drop off some hammer IIs and finish off the smaller ships.

Gardes = best against Serp and other Therm primary NPCs.
Wardens = best against Guristas and Kinetic primary NPCs.

But I typically end up using both in a mission (dropping the gardes when enemies start to get within 50k). For Ishtars in an anomly, I'll typically go with the Gardes because I'm still getting 50k range out of it.

I will close by adding that any serious drone user trains Drone Interfacing V and Sentry Interfacing V. It's a long haul and you may question whether it's worth the wait.... well. you'll be very glad when you've completed it. Tech II sentries with DIV are deadly.

you forgot about explosive resistance in gurista rats. it's about at 66% and kinetic at 46%.

Wardens dmg modifier against gurista 1.44 * (100-46) = 1.44 * 0.54 = 0.77
Bouncers 1.68 * (100-66) = 1.68 *0.34 = 0.57

Wardens are a clear winner here.

Wardens do penetrating damage, making them absolutely elite in most situations. Especially coupled with EM ammo.

Leave the EFT warrioring at home and run a couple easy missions first and check completion times, or times to kill individual ships.

And they are especially great with webs factored in.

Note that they are going to change the NPC AI. The rats will now shoot drones, making flying away from your sentries a bit more chancy. If the drones catch aggro, you will have to recall the drones then fly to them to allow them to dock.

Alternatively, you can fit a RR and orbit close enough to rep the drone being shot. You will not be speed tanking quite as well, but if the rats are shooting the drone you do not need to speed tank. Also note you can now control-click a drone in the drone window to target it.