Is this a 3rd option?
According to the exploded parts diagram.
O ring over the E tube, E tube into the jet block, and finally the gasket sandwiched between carb body and jet block
The emulsion tube (part #34) wide flange seats in the relief of the carb body passageway, centered in the venturi of the carb as pictured here (my attachment/pic).
Where it emerges on the other side in the float chamber, is where I install the jet block gasket (part #35), then the thin O-ring (part #33), and then the jet block (part #32, obsolete, not available), with its rubber plugs (part # 43, 45) in the end passageways for the two brass jets (part #42, 44) which screw into it.
The parts fiche shows the emulsion tube on the same side of the carburetor as the float chamber, which I believe is to show it clearly in its entirety. If you've disassembled the carbs and paid attention to the order of disassembly, you know the emulsion tube first inserts into the carb body from the slide/diaphragm side and then protrudes into the float chamber, where after placing the jet block gasket, the O-ring, and the jet block over the shaft of the emulsion tube, a brass machine screw (part #28, 29) and two small phillips screws w/washers [part #18, 19, 30, 31] (yes they're technically JIS screws, but for convention's sake, may we refer to them as 'phillips') secure the jet block to the carb body. Snug, not tight.
In deference to
dannymax, placement of the O-ring and then the jet block gasket is another way to do this, and may be the factory method. I've referred to the fiche to guide me on assembly, which is why I've mentioned gasket over the emulsion tube shaft, then the O-ring.