The board I used is Dx sku 7612 and though from the description it sounds like it is in parallel with the single mode board. It is, but only in the sense that the processor circuit on each multi-mode board is in parallel with the drive circuit connected to the amc 7135 chips and yes, it does work. That part is straight from the Oldlumens/Techjunkie and will work with any 7135 board, single, multi, whatever. Just run two leads from Vbatt; one to led, and one through the reed switch to the board. Power is always on to the led but current only flows when the Vdd pins on whatever board you are using are switched on. This part is tested by many others and verified most recently by me just yesterday.
Afaik, all 7135 chips are have the same outward topography, that is, they all look the same aside from printing, and the pins are all in the same relative position. Apply more than 2.7V to Vdd, and 350 mA can flow through the chip from led- to ground. This is the trick. If you’resoldering skill is up to it, you could concievably make an 8-chip sandwitch with no board at all.
I say the 7135 chips on the processor board are not in use because they aren’t. In my circuit, there is no lead from led- to the chips on the processor board, only to those on the slave board. My circuit is only using the throughput of the slave board, 1.5A.