I was going to say that
You'll have to optimize your launcher, don't hesitate to have a look at the tutorial.
I would say your launcher is a good basis, but you rely way too much on Hawk engines. For the boosters it's fine, but then the main core should use some efficient engines (Valiant or Frontier).
Then remove some fuel from the 1st stage and give it to the boosters to compensate. Because your core has less thrust you'll need the boosters for a longer time.