First RMH opnions setup needed

Okay so heres my first rmh second redesign. Already put a deposit down on a company to intall my 25ft tall indoor chimney but I need some opinions before making things permanant. My exhaust distance is roughly 20ft with 20ft worth of turns. With my indoor chimmey 25ft and it being so close to my bell should give me a good draft. After exiting the manifold the exhaust will slowly rise throught the run until it turns back around almost at the bell and should be riding above the first run and will take a 90° turn right to go out the flue. Some other factors. 8inch pipe, full 48inch firebrick heat riser. There will be a 4 inch airgap between the mass and my wall with a 1/2 durock sheet against the drywall with a 1 inch air gap behind that. My bell is 20 inches from the wall.
Heres a few pictures

Another

Kyler, you're adding unnecessary bends. At the end of the bench, i would make a mini bell, with the two pipes sticking perpendicular in a half barrel (or a smidge more, as you wish)

This would eliminate the cost of 4 elbows, and act supposedly as 2 elbows, but spreading the heat the whole length of that mini perpendicular bench. As well, the mini bell is better at letting the gases turn without friction. So it's easier on the flow.

JMHO.

Yeah the only reason I added that was to get more length out of my exhaust. Otherwise it would have been about 14 ft of exhaust with a 25ft chimney which I feel would have been wasting a lot of heat

Im cant exactly picture what your talking about either...im trying I promise haha