One other key point the other answers missed -- because they're tubular, cylinder beads (Delicas and Treasures) have larger holes in the center, which makes them better for needleweaving projects where you will need to run thread through the same bead several times.

DEJ

Delicas are very consistant in size, making them great for stitched patterns like peyote work. They are alos tubular. Hope that helps!

Delicas are a brand of seed bead produced by Miyuki Japan, which makes a variety of other seed beads. Delicas are also known as cylinder beads in some projects and magazines. They are nearly perfectly square shaped when viewed from above, whereas other seed beads (Japanese or Czech) are slightly bowed out at the sides - think barrel-shaped. Delicas are almost completely uniform in size, making them great for projects requiring regularity, like loom work or square stitching. Delicas are produced in a HUGE variety of colors. The color palette selection and extreme regularity meas that Delicas also cost a bit more than many other brands of seed beads. Also note: a Delica size 11 is actually closed to a size 10 when compared to other brands' size 11 beads: Delica 11's are a bit smaller than Toho 11's or Jablonex 11's, for example.

Melissa Post, Pug Beads
www.pugbeads.com

Size 15 seed beads may be made by a variety of manufacturers and come in different shapes and finishes. They're also called rocailles when produced by Japanese or Czech companies. I prefer Miyuki Rocailles and Toho's.
Delicas are a proprietary manufactured shape and size by Miyuki, Japan. The most common Delicas are marked siz 11, and they are closer to an actual size 10, and are significantly smaller, not to mention more regularly sized, than other size 11 seed beads. Delicas are aslo available in size 15 (closer to 14) and 8 (closer to 7) and 10 (closer to nine) from select retailers. Delicas are cylinder, with no outward curving at the sides. They are also available in a variety of colors and finishes. Delicas are the preferred seed bead for painstakingly regular peyote and loom work.

15.0 are very small and round, delicas are almost like 11.0 and I would say cylinder in shape.

I do not know if I am right it is just my take on it I like to use both

Delicas are cut so exact that they fit almost into each other, whereas the seed bead does not.

For sure. The large just means the bobbin has a longer length of thread (250 m rather than 60+ m). Nymo D is usually the size thread I use for beadweaving.

Part of that depends on whether you are using a #10, 11, 12 or 15 needle. And, if you using beeswax or not.

I would use Nymo B with an 11 or 12 needle. Depending on your project, double up the thread.

Fireline. It's created from highly durable material and braided for extra strength. However, it's still a good idea to pass through your crystals a second time if you can to minimize the possibility of their sharp edges cutting the thread.

Thank you for your inquiry. All of our seed beads are sold in an 8 gram package. It is difficult to know exactly how many are in each package, as each of the beads are slightly different in size and weight. We have listed the approximate bead counts for most of our seed beads in the main description of each category. We hope this is helpful!