What is with your code? Shouldn't it look like this:
-snip-
of course, with the channels, represented by dot, in each diagram being the same ones, just on the next level down or up?
It's because I decided to use the [ code ] tags to ensure that every character was the same width, which is often beneficial for creating diagrams so every column of chracters is actually lined up. I probably should've used the [ tt ] teletype tags, which have the same effect but don't put them in a seperate window and so don't shrink everything, but oh well.
You sir, definitely deserve a wiki spot for this!
This is the general layout for an 'ideal' floating pump stack (least space used, least flows, least mechanisms). As stated before though it may have problems with magma staying in the side pockets. One possible workaround is to build from the bottom up and 'prime' each input/output layer as you go with a pump operator. Perhaps no magma needs to be in the stack, even, and the 'priming' is done solely to desynchronize the whole stack, which *may* lead magma to fill the side pockets. This will almost certainly be more micromanagement in the construction phase, as no pumps in the middle can be pre-built (as with any floating stack, but extra delay in between placing pumps due to getting some lazy dorf to the finished pump), but you can still desync the stack from both the top and the bottom and then link them in the middle. Or hey, power/pump the whole stack WHILE building (can be very dangerous fun). Then, each pump layer built is already desynchronized.
Powering the stack while it's being built isn't actually dangerous, as the magma chambers on each layer are of course sealed anyway. If you've got leaks, it's actually probably safer to have just the one level leaking at once instead of all of them suddenly starting when you finally start the whole thing up, so when practical running power to the bottom level is probably a good idea.
If the numbers people are posting are true, then there's already no doubt that you need some extra magma floating around in your pump system. Now the question is how little can you get away with, and how simple can you make the stack. Does the magma in the side pockets NEED to be 7/7 to heat the tiles above it? Is there a difference between 7/7 and 1/7 for heating the side walls and floor? Can something simple like desynchronizing your stack provide the means to solve this problem?
When I started the design up for the first time, it didn't immediately fill each reservoir all the way, so there were 1/7 magma tiles on many levels. I noticed no increase in FPS between the first time I ran it when it wasn't 100% full and the second time when it was, so it's probably just a matter of "is magma present in adjacent tiles?," not "how much magma?"
...Dangit I knew that idea was too good to be unclaimed.
Anyways, Under "brilliantly stupid" you could solve the cleanup problems by replacing the floors with hatches (or more likely bridges) and channeling out the sides of the uptake tiles.
-snip-
It's a clowncar of a lot of work though.
Yeah, most means of draining magma reservoirs in general take a fair amount of effort, and this design of course makes it so that there are dozens. It's tricky and dangerous work, but then again everything involving magma is.
Also, I've now done a bit of tentative testing on the 2x3 head-over-head reservoir design, and found no significant FPS drop while it was running (it filled the magma forge works quickly, so hard to say how it'd work in the long run). It appears to work just as well as the original 3x3 design, as Trouserman's and my theorizing earlier suggested it would.