[Eliot Ness]

One of the larger chassis I work on are 1938 Zenith 9 & 12 tube chassis (same size).  I was going to test the size limits of the stand but these chassis have a ridge that prevents the fixture from sliding on:
   

So I shrunk the chassis stand down as far as it would go and it did accommodate my tiny Detrola 4 tuber (model 4D):

   

Great job Simon      Thank you!