Is RF Transformer Impedance Significantly Affected by Wire Size?
Here is a chart to show wire gauge variations.  You can see the resistance per distance column that using #26 opposed to #30 you are getting ~135 ohms per km versus ~340 ohms per km. If you got the proper number of turns, I wouldn't expect it to cause the radio to fail, but keep it in your notes as possible troubleshooting points.