Beware that the plans in Model Railroader may not be correct for that FEC cupola caboose! I was told by a second generation FEC engineer and HO modeler that somehow the MR plans show the sides of the FEC caboose to be lower than the prototype (I believe the figure mentioned was 9 inches too low). The Overland brass HO model was made to these plans and was also said to be incorrect. There is one example in poor shape at the Gold Coast RR Museum, but I'm not sure it can be measured because it is wrapped in tarps.
Bill in FtL