What a rad story of arriving in Cabo and doing their little race. Super cool.
You will have a great time on this 1000 course on your big bike. Other than the whoops by Felipe that BajaDad mentioned and the 30mi of whoops near Constitucion your bike will work fine.
I've raced a 1200 HP2 to La Paz a couple times ('04/'06 with good results) and I was pretty much a newb to giant bikes. I'm also about the same size as Larry so judging by the pic of you guys towering over him you guys are fit to those bikes just fine.
Silt? No worries, just go around it (no matter what you're riding).