Before we go too far on this, consider wasting an e-6 slide film.
Process it without exposing it. The result is a 'black' film.
I undertand it is substantially transparent to infrared.

Why not make a 4.5" square filter by taping two sections of this film side by side, slightly overlapped.
Then make a cardboard holder to fit a folding fan reflector to allow the light from the falshbulb to go through this filter?

The other variable we must contend with in using this 70 odd year old article, is that I am pretty sure it is talking uncoated flashbulbs.
There is a reference to dying a cellophane safety bag for placing over the flash bulb. I had never previously heard of such a device, but it makes sense).

AFAIK all 'modern' ie from the 60's to perhaps 80's flash have a coating, and the B variation ones have a blue tint to the coating to boot to yield a daylight favoured output from the flashbulb's luminous emission.

So it is possible that the amount of glycerine and liquid could be cut, because the plastic on the lamp only must be dyed.

The original 'recipes' would presumably work best with non B coated bulbs.

Concentrated dyes are unbelivably dense. I was consolidating two partially full methyl violet bottles to cut down on the differernt dye stuff bottles after initailly doing an inventory of them.

The emptied bottle had but a faint dust on the inside and dust inside the cap as well. I placed them in the bottom of the laundry sink, and turned a gentle stream of cold water onto them. A vivid purple liquid resulted, and continued to be produced for over a minute, from just the action of the dust.