Steve, I've just tried this with 4x5, not sure if the drums that the article uses will work with 5x7. It took me looking inside the drum to realize what he did also.
Basically when you look inside the drum, you'll see 3 plastic dividers along the wall. If you're facing the drum opening with its "feet" pointing down at the floor, you see the v-shaped divider at 12 o'clock position. Then the other two at about 4 and 8 o'clock positions.
The film sheet's long side will fit between one side of the v-shaped divider and one of the other dividers.
So you can fit two sheets on the two sides of the v-shaped divider with the emulsion side facing the center of the drum. In other words, one sheet will spread between 12 to 4 o'clock position, and the other sheet will spread between 8 to 12 o'clock position.
Now, in a darkbag/darkroom, you can slide the two film sheets all the way towards the bottom of the drum.
The spacer goes in next, clamp it on the v-shaped divider, slide it as far as it will go. Once in place, the spacer will hold the two sheets in place, then you can slide in two more sheets (each side of the v-shaped divider) until they hit the spacer and can't go in anymore.
Then put on the lid and you're ready to develop the films.
Am I further confusing you? 😀
Btw, I really like the results, even development with 300ml chems for up to four 4x5 sheets. What else can you ask for?