I also have a set apart on my bench right now. They are from a Greener Monarch made in 1899.
Left barrel OAL of the bottom from tip to tail is 44mm
The spring is 42mm
Right barrel OAL of the bottom from tip to tail is 43.5mm
The spring is 44mm
The left tail has been broken and welded before. It broke on me at the larger diameter rod ahead of the tail and I just had this welded back together. Need to file and fit it now...