The tinker spec has been cowered 4 times, if not more, over in this very thread.
But lets go one more time.
Offensive;
Gear and talis focused to max out DMG bonus, overflow into def, either armor/tou.
RR mainly in crit then avoidance.
Main trick is to keep your turret stacks as high as possible at all times. Then you you either;
A) Run in with AB -> RDeploy -> FB -> LR -> BB/SD spam, then reapply/redeploy FB and LR once they are off CD unless everything is dead already.
B) Magnet on top of FT -> FB -> LR -> BB/SD spam.
You can use Strafing run as aoe KB if enemy is very close to an edge / soft tank line breaker [the punt is minimal] or just as filler aoe dmg. It has significant delay from initial cast to actual dmg so may be layered on top of other insta cast abis like BB or SD to create a micro spike moment. But as it gives immunities and can displace enemies from intended aoe pressure spot should be used sparingly and/or with prior consideration/care.
In both cases you want flame turret to be on top of you with as many stacks as possible for both bigger DMG modifier and ranged avoidance buff.
Ofc this exact setup is meant to be only deployed if you have both guard and heals or very good heals.
Defensive/support
Lets be honest this build is gonna be you stepping down as dps and assuming a "lets be extremely annoying to enemy yet still useful to the group bastard" stance. If you have more ppl interested to assume such a role in your grp/wb, you can spread the utility tactics and slot some more def/dps focused ones on yourself. No WB should have more than two pierce def/concussive mines engis IMO for example. Some tac can be left out if one of grp mates is already covering it. [healers/ib with ap tac for turrent ap / SW already running pierce def / ST disorients] So the exact tactics layout depends on scale / purpose /comp of GRP/WB.
Gear and Talis should be focused towards def - mainly armor as you will be having much easier time against range due to the flame turrent dodge/disrupt buff, RR in mainly in avoidance, leftovers may go into crit or rr abis.
Then you mainly;
A) Act as a Magnet Bot
B) Act as debuffer
C) Provide an weak off Heal
D) Create a distraction and gather enemy hate
E) Mix of some of A/B/C/D
F) Mix of all from A/B/C/D
Ability usage wise you gonna spend most of your time spreading AB, throwing mines on enemy back lines, keeping keg and turrent near your friendlies and generally being a nuisance to the enemy. You can add in some dps using pretty much the same rotations as offensive one but with much less umf to it.
This setup is more friendly towards your survival chances and you provide decent amount of support but don't be surprised if you don't contribute much in the pure dps compartment. In the end it is nice to have but should be only added into the comp if you already have some decent dps pressure going for your grp/wb.