150 boyz in theory is a nice thing, but in practice you just can't fit all those boyz on the table without bunching them up tremendously and becoming vulnerable to blasts. Really, anything beyond 100 models you're going to run into issues with deployment area, not to mention the difficulty of moving all those models in a timely fashion for a tournament.
Things that get around the deployment issue:
-Snikrot kommandos: they come in on any edge, typically right behind where they need to be, awesome.
-Lootas: they stay back and only crowd initial deployment. Afterwards, the rest of the boyz don't have to crowd with them as they all move across the board. They will also help you a ton for taking down vehicles and are pretty much required in any footslogging Ork list, IMHO.
-Deffkoptas: if they outflank, they won't be crowding deployment. I'm not a fan of them, but it's an idea.
A few other things:
-Grot riggers don't help the kans at all. If a kan in a squadron is immobilized, it is destroyed due to the vehicle squadron rules.
-Ghaz will slow down whatever unit he's with to count as always moving through difficult terrain. You might be able to just deploy him with whatever mob is going to have to run through cover anyway, and then it's no big deal.
-Shoota boyz are really handy for footslogging armies. You might consider them for the squads that aren't 'ard boyz.
-One KFF really can manageably cover 2 boyz mobs and 2 kan mobs, but is insufficient to cover 150 boyz and 9 kans. 2 is what this army really calls for at this size, and ghaz hurts you as much as helps in large part since he guarantees a 6" WAAAGH! But the unit he's with loses a few inches with every movement due to his slow and purposeful.
I were you, I'd swap Ghaz for another KFF mek and change out 2 boyz mobs for a loota mob and a snikrot kommando mob or 2 loota mobs. That's still 90 boyz plus another 30 specialists. If you have the points, you might also consider a gretchin mob to cover and assault screen boyz/take and hold objectives/whatever.