I have read all of the threads about each of these operations, and while I think I have a solid plan, I thought I would start a new thread to tie things together (pun intended).
The directions call for closing the back, then building the chimney, then removing the form. An emerging, popular, and maybe preferred sequence seems to be building the chimney, removing the foam (after sufficient drying time), and closing the back.
I finished my arch yesterday, and my plan is to lay the chimney today then leave my oven alone for 9 days, when I return from moving a daughter to VA. Of course, I am dying to take out the form, and could do so as late as Saturday (4 days of drying time) before we leave, but the trip provides a natural and forced break for a good stretch of drying. I would then remove the form and close the back after the arch and chimney have been drying for 9 days.
So, my sequence would be: lay the chimney with the form in place - leave the arch and chimney to dry for 9 days - remove the form - close the back.
I know my planned sequence does not follow the Brickwood directions, but there seems to be a good amount of thought and success behind changing up the steps, especially with sufficient drying time.
As always, I appreciate all the help this forum provides!