Casting silver removable caps

I’ve got a few questions that I have yet to find a solution to. The first question is casting thin metal designs. I know for designs with lots of details that I am supposed to cast at higher temps of 900-1100 degrees fahrenheit. I assume the same would be for thin metals. The first picture was my original mold with a thin layer of wax around it. I destroyed the wax trying to get it off the mold.

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Then I went back, and made a thicker wax covering, then researched how to remove the wax. The problem is when I casted at 950 degrees, I still had holes show up in the caps even though the wax was really thick. Then just to check to see if what I had would fit, I noticed the metal shrank, and wouldn’t fit my mold after doing some light polishing. This thing is also extremely heavy for caps. It weighs almost 20g. Normally 6 caps weigh between 1-2 grams. What am I doing wrong other than needing to improve my wax skills?

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I’m using srs investment casting powder, perfect cast for the mold, and some random Chinese sheet wax to cover the teeth. Any help or insight would be much appreciated.