How to use wat tambor

Personally, I think he’s put to better use making otherwise unviable team viable. GG led droids are already pretty awesome on their own, but there are several other mediocre teams that could really use that push to take them over the edge. A good example for defense is Nute (L), Jango, KRU, Wat, Dooku. The AI will pretty much always use the shield generator on KRU, which makes him a real pita to deal with, and if they’re in the back lane in GAC can throw your opponents for a loop.
If you’ve got your FO team geared up, he also works well under zKRU as a time-out defense team. If you put them behind your bugs, chances are your opponent used Nihilus with Traya already and they’re gonna have a tough time nuking A permataunt KRU (health/prot gain every time he’s debuffed or buffed, plus auto cleanse, plus immunity to percent health). If you’re looking for something for TB, he’s gonna need to be seriously geared up since geo TB has a lot of AOE attackers. If you’re not already 4/4 with GG droids, you can put him in there (I’d probably sub out IG-100, or B2, personally). Put the Blastech on an R7 health modded GG and watch him go. Alternatively you can put it on B1 so he can spam life up and keep your troops healed up.

Wat is amazing and will pretty much improve any team you put him on. The only downside to Wat is that you only get one of him.

I'd say droideka.
Gg, b1, b2, magna and wat can be pretty hard to beat

He's great with Hoda and C3PO

just use him with SLKR, duh! But yeah in a gg team I would replace DD.

for sure give wat the zeta, he will go before anyone (besides Han) and put tech on someone

He's the best plug'n'play character in the game and easily a top 5 char (2nd best char after SLKR and before GAS, Rey and Malak on my own list).
For early players he's great as a defensive addition to Nute / KRU teams or to use him on offense with KRU and FOX. Also for 3v3 a Nute, Wat, 3PO team is a nasty sleeper team that can easily catch your opponent off guard.
For mid range and long term players he's great as defensive addition to a GG squad (if he's g13 and modded with sliced health primaries) or part of a GL Rey counter.