Brick for new to me evaporator

[Loch Muller]

So after kicking the idea around for a while I've pulled the trigger and made some significant upgrades to my maple operation including a used GH Grimm 30"x8' raised flue evaporator, stainless sap tanks, vacuum setup, and some tubing. My wife and I are pretty excited that we'll be able to process in a couple hours what used to take us all day on our 2x4 arch. When I picked up the evaporator I had to remove the fire brick to be able to lift it. 90% of the bricks crumbled to pieces when I took them out so I'll need to purchase brick to reline the arch. My question right now is should I
1) reline the arch with full bricks the way the previous owner did
2) reline the arch with full bricks and ceramic insulation beneath them
3) reline the arch with 1/2 thickness bricks and ceramic insulation or arch board beneath them.

Also I'm thinking that I might be able to just use arch board and no bricks in the back of the arch past the point that wood can reach. Does that sound right? Thanks for your opinions.

Bill

[jmayerl]

Fire box-1" of blanket then brick over. On my gasifier I have 3 rows of full brick then top two are splits. Under flues- insulation then some sort of board so you can brush the flues easily, I used 1/4 cement board.

[lpakiz]

I placed the first couple rows of thick bricks flat, to yield a 4 inch thick wall. Next several courses were thick bricks, on edge. The last 2 courses were splits, on edge. Gives a nice taper and seems really stable, with the wide base.
Not to disagree with jmayarl, but I just left the back part as blanket. I cut a piece of lumber just long enough to lay crosswise on one of the ledges in the fire box. I can "lever" the flue brush up into the flues without too much trouble. If I had known that cement board would survive those temps, I might have done as Jeff suggests.