I’ve commonly gone with the knight’s amulet since the turret build I’ve used is defensive in nature. The enhanced toughness allows for nice durability, and then I also have some power and precision to deal damage with the rifle (although those stats don’t help the turrets).
I think solider’s would also be a good choice since it helps prevent you from being overwhelmed by conditions. There’s also the barbarian amulet, but I don’t feel that’s as strong a choice for an engg… although it might be if your opponents have a ton of condis. Clerics might also be a possible option, although you’d have to make sure to greatly utilize your healing power to be effective.
I’ve never done a condi-based turret build, so I’m not sure how well settler’s or rabid would work out. If I was to do a condi-based turret build, I’d probably go with rabid.
As for the turrets themselves, I generally always pick the thumper and rocket turret.
The thumper turret is more durable, so you can generally rely on it to be around during combat. It helps you kite people while staying on the node, does pretty decent damage, and its overcharge can be quite effective (especially since people tend to lose track of where the turrets are/what they’re doing during the fight). This also gives you access to a stun breaker, which is always handy to have. The overcharge and tool belt skill also provide additional blast finishers, which can be useful for certain combos.
The rocket turret is useful for some high damage AoE (helpful against minion masters, mesmers, &c.), and the overcharge is an additional source of CC. It’s also a handy thing to place off of the node (i.e. up on a ledge) so that the turret is never in danger of being killed. The tool belt skill is a bit janky to use, but can be used for some nice burst damage at point blank. Since I generally use experimental turrets, this also provides me protection uptime, which is useful for defending a node.
If I’m running an additional turret (healing turret for healing is implied), I often run the flame turret. The reason is that the tool belt allows me access to a fire field, the turret is a bit more durable than the other ones, and the burning can end up being pretty decent DPS. Furthermore, the overcharge helps me stay on the node as it blinds people, which I can also use to enter stealth if I want to combo on it (useful for rezing a downed ally near the turret). I also tend to run experimental turrets, so the consistent might uptime from the flame turret is really handy.
I think the rifle turret and net turret could still be very handy though, just for different purposes. I think running the rifle and rocket turrets could be a bit redundant, although it would definitely be good for damage output. I don’t feel the net turret is as handy for node holding since you generally have less room to kite, but it might be quite useful for team fights. The rifle turret could perhaps be an alternative to the rocket turret if you prefer how it works, though I generally take the rocket turret as one of the default ones.
Of course, you might just be better off with a kit instead of a third turret (i.e. bomb kit or elixir gun).
I played quite a lot with pistol/shield and turret but now i begun tho think that rifle is better for the fact that i can throw away melee opponent from me and from turrets