Looking solely at the Model 1 (also called the "Popular" model), it came primarily in the 24 inch frame size and a 26 inch (!) frame size with 28 inch wheels. These bicycles were ridden in a somewhat archaic way by our standards today. In earlier times, stand over height was much less important than today. The bikes were tall, and many people could not touch their feet to the ground while in the saddle. The bikes were mounted with a push forward and swinging the leg over and onto the saddle in one motion. The tall frame allowed the rider to get the full leverage of the leg while the tall stand over height provided clearance for rough road and ground obstacles. The riding style of the time emphasized constant movement, and there were fewer cars/stop-and-go traffic to deal with in the early part of the 20th century. The DL-1 is very much a holdout from that era.
The whole "tall people"-specific advertising for the 24 inch frame came later and as a contrast point to the Raleigh Sports bicycle (DL-22). Technically, the advertising is true in that tall people would like the DL-1's size, but it's misleading to say the DL-1 got its dimensions specifically because tall people wanted to ride it. Its design is a relic of the early 20th century.
If you didn't like the very tall stand over, you could buy what was called a "safety" roadster - say, the Raleigh Dawn series. These bikes had lower bottom brackets, included smaller sizes, 26 inch wheels usually, and you could easily touch both feet to the ground with your backside in the saddle. Hercules also offered a "safety" roadster model, and even a "compact safety" model. Hence, the "safety" term - you could stop the bike in traffic while bringing both feet down and keeping your backside in the saddle.
The Raleigh Dawn series often used the same frame dimensions as the Raleigh Sports, so the Sports was a "light" roadster with a safety style configuration and a couple frame sizes in the 26 wheel pattern.
