I am looking to participate in the Worlds Escalation tournament. Do i create a 150 pt fleet and break it down? Or create a 60 point fleet and work my way up ?

Both are legitimate ways of creating the fleet.

I like the former, as that means you've got a bit more guidance as you build (knowing where you're going is important!).

However, quite a few 150 point fleets are unfeasible for escalation, so don't be afraid to simply scrap your ideas.

Typically, you want to put the pure core of your fleet in Round 1, so you have them in all rounds.
Your Key Supports (e.g. Howlrunner) can wait until Round 2.

The first round suffers the least from taking a large initiative bid. Anyone who wants to run multiple larges will typically float around 10 points, to afford having the two in the 90 point fleet.

Similarly, the 120 fleet is more forgiving than the 150 point fleet for such point-bid shenanigans, though you do not want to float more than 5 here.

Check out my "Escalation Compendium" (that I'll be updating to day: I went on a bit of a hiatus) to get a feel for how several of us on the forum have been thinking about this issue