Commercial 2'X6' arch stack size question

[MISugarDaddy]

I am considering upgrading to a 2' X 6' evaporator for the 2016 season. Our sugarhouse is set up with an 8" stack currently and I would prefer to not have to change it since it is all new stainless stack. I stopped in to the local Leader dealer to get prices on the upgrade and learned that Leader's 2' X 6" arches come with 10" stacks. What I would like to know is if all the other commercially built 2" X 6" arches come with 10" stacks or if some still are made with 8" stacks? The Leader arch that I am considering is the "Inferno" air-tight arch. Does anyone have such a unit with an 8" stack?

[maple flats]

My old leader 2x6 had a 8" stack. I think you will be fine. If natural draft IS an issue, just add a few more feet on top. You may then need to brace it. If buying a 2x6 designed for a 10" stack, I'd use the one you have and go from there.
Since my roof is steep and the walls are 10' high, my 8" stack on my old 2x6 was 17' tall and it worked well. If the extra SS stack is not in the budget, just add galv. on top for more height, then plan to change to SS in a year or 2.