A combination of both. A little quicker to unwind and use line that has coil memory. Larger diameter coils leave fewer curves in the line to be straightened, and the arc of the coils are a little closer to being straight than smaller radius coils. And a little bit quicker to wind line back onto the spool.
Both the Meihō (メイホウ) and the (rādji) Raji Leica (ラーヂ ・ライカ) spools tend to make line spools that jump in size by 20mm; from small, to medium to large sizes. The raji leica about 5mm smaller in diameter. An increase of diameter of 20mm = about an extra 2.5 inches (6.35cm) more line wound onto the spool for each wrap round the spool. 5 round turns = an extra foot of line wound onto the spool. Plus I do not find carrying the slightly larger line spools a burden. As some people do.
I most often carry everything extra I want on the stream in a Gossamer Gear backpack hip pocket, that I have attached a shoulder strap to. It is about 7 in x 4 in x 1.5 in. Big enough for a small fly box, spool of tippet, my car keys, an extra line spool or two, but it becomes a little crowded with 2 line spools. The line cutter and forceps attached to a dual keeper, the forceps conveniently clip to the belt loops of the hip pocket. I figure if I can’t carry all I need in it, then I am wanting to carry too much stuff.
I realize – It is only a small decrease in time, but ever since reading a biography of R. G. LeTourneau, and reading his story about one of the principles he applied to his work I lean toward thinking about time efficiency of doing task.
The story he wrote about was when he was a young man, working at one of his first jobs in a foundry. He was working hard shoveling foundry sand like he was putting out a fire, and working up a sweat. The boss walked by and said to him, “Young man I do not require you to work hard - I only require you to work fast.” One of the reasons why he invented and built machines that did work fast. My wife and I are at odds about this. She wants everything in the kitchen stowed behind cabinet doors, out of sight. I want spices, and pans out in the open where I can find and use them quickly. Since I am the chief cook and plate washer now days I favor my view prevailing. But ya don’t always get what you want.
Anyway, you can find a lot of different Japanese style line spools by doing an internet search with these Japanese phrases:
- 丸型 ライン 巻き 仕掛け that basically translates as - round shape line winding mechanism / device.
- ラーヂ 丸型 仕掛け巻き = Radji round-shape gimmick winding
- メイホウ 丸型 仕掛け巻き = Meiho round-shaped gimmick winding
- 渓流 テンカラ糸 巻き = mountain stream tenkara thread winder
- テンカラ ライン 巻き スプール = tenkara line winding spool
- 丸型 ライン 巻き スプール = round-shape line winding spool
Of course you can mix the individual words around to make a different search phrase and sometimes find something different. Different model or homemade line spools.