Nice, huh :)
Kinda my own pattern as well. Started using a pattern from a book, but it had a funny second row, so I kept making new coasters to see how it worked versus a different way to hook the coaster up. They're all made with the Morris & Sons Avalon 100% cotton. The pink & purple ones are using the 4ply and the green was made with a bit of leftover 8ply.
You can see the different the ply makes to the coaster. The 4ply coasters were worked with a 3.5m hook and the 8ply coaster was worked with a 4mm hook. They are all the same diameter, however the green 8ply coaster has an entire round less. I've also worked a round of dc around the entire coaster to give it a defined edge, something I think that the coasters need.
One of the other things I wanted to trial out was a different way to start of a new row in the round.
If you have a look at the above picture, you can see that the two circles look a bit different. There's a pronounced downwards line in the coaster on the left, but the coaster on the right fails to have this.
Traditionally, you start a new row with ch stitches. I worked this coaster in treble crochet, so my new starting row was 3-ch. But I'm not particularly happy with it, since you can visibly see where the new rows start. So, I asked a few of the girls on the Krista group that I'm a member of, and the majority who answered said they started with a dc+ch. Some of them started with a dc+1ch, and some of them started with a dc+2ch.
You can see with the right coaster that the starting row is more camouflaged than the coaster on the right. I was much happier with the way this looks, so I'm going to continue working a dc+2ch with a new row from now on. I have to do a bit of experimenting to see how it works on a piece with rows, rather than in a round.