Can I use clay to make gauges?

I went to Michaels craft stop bought fimo clay and it works good! My ears are at 1/2 now .but the problem is u can make one but try making the other and it will be to thick u can't make two perfect sizes. I had to do one ear at a time. And I made tapers. Then bought silicone plugs fir 5$ each. The clay was 99 cents I think .tapers are bad for ur ears by the way and shouldn't be left in long periods of time