I have moved to a laser. I am not sure the guages you are talking
about. But with standard guages, at one time I had two meco torches,
one larger jeweler torch and torch for casting. I first installed
the flashback arrestors to the guages then attatched multiple Ys to
that. Also my bottles were not close enough for the length on the
meco hoses. So I had standard large welding hose with an adapter
attatched to the meco hoses.
I would not use aquarium hose. I know the inside of the hose is
plastic but I like to think the mesh wrap on the outside is flame
retardant and the plastic is higher pressure hose than aquarium
hose. (I have had lots of burning hot sizing pieces pop out onto the
floor over the years.) When casting I would turn off all the other
torches. Until the pressure equalized in the hoses the small flame of
the meco could go out. I didn’t want to have gas coming out of the
unlit torch. Hope this helps.