Last night I played with numbers on the spreadsheet. The only fixed costs that I have to work from right now are the cost of bunks, so I am forced to estimate the rest. I have a good handle on meals based on last summer's catering menu, but that is subject to change. Other things (supplies, shirts, nametags, etc.) are based on prices supplied by the Seattle CM or Momma and my local experience with events for Scouting/Cadets/Guiding.
My current projection puts us at $235 PP using only the 17 spots that are taken. I am crystal balling for a year from now, and there will be 3X as many attendees, so many costs will go down (economies of scale). For me, the biggest question is with the catering budget.
In any case that is your budget update. For folks who are sitting on the fence waiting for a better handle on costs, I won't be able to nail down the budget until January at the very nutty earliest (ie. don't count on it), but this at least gives a starting point.