I was thinking even mono white when you talked about tribes earlier. But if you go Boros, I suggest not forgetting
Embercleave. You can get that out t3 if you start with 3 one-drops, which is probably your plan anyway. It doesn't one-shot people on a weenie, but it's still a mighty blade. Triple
Fervent Champion into it would be 19 damage on t3. There's even a possible t3-kill for you can play another
Fervent Champion and
Embercleave on t3 - doesn't require all Fervents even.
How is the mana for Benalish Marshal? 4 Mountains don't cast it and 4 Tournament Grounds don't help the checkland.