The swirls look great! They are very forgiving to mistakes too. If it makes you more comfortable, you could try to match the top thread to the color of each block. After a few quilts, I'm just now getting brave enough to use a contrasting color.
On your first sample with the 1/4 curved triangles, the bottom right looks pretty good. There is definitely a learning curve with FMQ. Don't forget, once it's washed and puckers up a little, what you consider mistakes, others won't even notice. :)