Thinking about it some more, and I think a better answer is...
More than any special godnames, or colors or any such; the thing that makes a circle thelemic
is that you understand what the circle is for and then design and construct something that fulfills that purpose for you. After all in your own magical circle whose authority would be higher than your own? The idea of magick is that you are artistically creating something, not technically reproducing.
I learnt a lot from constructing GD style implements, with specific measurements, colors, patterns etc.. I was much more challenged and learnt a lot more from the thelemic version, where I had to discover first what my personal symbolgy was and then create it.
I'd suggest you read the chapter from Book 4, and look at a few versions others have created, and then think about what would make them a better version for your own use
Then have fun creating it