So I'm a Tohaa player. I've posted two games with Onyx and have very little idea of what I'm doing with them. I take 4-5 Unidrons. Plasma Sniper for long range engagement and Spitfire for short. Or when the Sniper drops and I need to be aggressive. F/O with extra points. I'm thinking of taking extra Unidrons to shed. Deploy the Sniper higher, the rest lower, so he can drop out and maintain ARO presence. And the link can run off and Spitfire things. I don't take a Nexus Hacker Lt anymore because he's too easy to murder. Tell me, how do you use your link? What triggers do you look for to change roles?
The plasma sniper is great, but recently I'm finding the ML to be just as potent as an ARO piece, if not as much in the active turn. I tend to use my Unidrons defensively, however. They are cheap, and supply the orders for my more aggressive pieces, so I don't care very much if they end up not advancing. That said, I like the idea of bringing 5+ and only putting one of them on top of a building or something and switching the link over when it's time to move them forward. I have to brush up on fireteam cancelation timing and triggers before trying that, though.
Like Sabin I've found the ML to be marvellous. I think a combination of a cheaper profile, 3 saves and a better chance of catching extra units in the template edge out over the Plasma Sniper for me. When I build Onyx lists, and specifically with Unidrons, I will always have redundancy for the link in the list. As they're not exactly the best shooters in the game, they will die. When that happens I like to have a unit nearby that can bring the link back up to 5 members, this is usually another Unidron or a Nexus. Spending that extra point on a FO profile over the 14 profile is a good choice unless the mission involves killing specialists, the Flash Pulse will give you a meaningful ARO out to 24".
I tend to run ML/Sniper for a firebase team with some FOs sprinkled in and use them as basically a firebase. If I'm going active killing I'll slot in the Spitty or K1 with those two suspects.
Don't forget you can use the Nexus or Legate spitfire to fill that slot. No marksmanship, obviously, but they're both *waaay* better at running solo if the team breaks.
In terms of running a Nexus Hacker, I like it in the link but make sure that the link always has the K1 combi + tinbot. It really helps the FtF odds of the hacker
Defensive bunker with 1-2 heavy weapons and a nexus LT hacker with them for supportware is a good one. I also like the 3+ specialist short range team you can use for pushing up the board - use FO / K1 Unidrons as meat shields for an Umbra or Nexus to get into position, and put a couple of spitfires in the team, it's honestly pretty solid this way too.
I like this but with an E-Drone, you can go hard on double supportware for HI/TAG attacks and can also provide offensive supportware without activating the entire link.