|No, no, it's van Guard. It's Dutch.
The first question, of course, is what do we replace, the Evade or a Brace token? It's up to you if being a Fake Assault Frigate with an Evade-Redirect-Brace is better/worse than 2 Braces and a Redirect; it'll depend on how you fly it and how you plan on moving into and out of danger. Easy answer is if heavy squadrons against you, replace the Evade. If mostly light squadrons, use a Brace. But it's situational and lets YOU decide.
Now then, what Weapons Team? So MANY good options here, really. There's a Ruthless Strategists Escort Neb with 2 dice of flak and a 3rd potential point of damage into whatever squadron you're attacking, there's a Gunnery Team version if you just want to double tap out the front at long range, there's a Flight Controllers version if you want a carrier, etc. The way I look at the Vanguard is that it's the vanguard of my forces; leading them in and letting something else deliver the killing blow. So if I want a carrier, have Yavaris coming in behind it pushing some squadrons after Vanguard clears the others out with Ruthless flak or Flight Controllers (it's also a great spot for Rex!). If I want an initial punch for my forces, have Salvation or several hammerheads following up as well.
Sample build that I will need more games with:
Neb Escort (57)
Captain Rex (5)
Auxiliary Shields Team (3)
Linked Turbolaser Towers (7)
Ruthless Strategists (4)
That's an 80 point build for basically a fully upgraded Assault Frigate. Is that better or worse than an Assault Frigate? No idea, but it's CHEAPER, alright. You can do similar with Gunnery Teams or something like that as well. The ability to create 2/3 of an Assault Frigate (health and firepower wise) for the cost of a basic Assault Frigate is mighty nice and definitely worth exploring.