We've recently added a fresh line of small contemporary singing bowls that are of very good quality. These bowls are extremely well made and sound even better. They also compliment larger singing bowls very well and sound incredible (especially when the overtones produced by the bowls interact with one another).
Here's me playing two of our bowls at our living room floor. One is an old Tara bowl in G# (17 cms) whilst the other one is a small contemporary bowl in C (6 cms). They were purchased recently by one of our customers in NSW. I don't think there is a right or wrong combination since base notes and overtones vary and it's best to go with one's liking.
The bowls sound amazing and hopefully the iPhone video below is able to capture a bit of the surrealism. We also have a large compassion bowl and will soon post a video of that with one of our smaller bowls.