I had the finishing kit and the FWF kit along with the fuselage. Seems there was always something you could do having all the parts. Some things are nice to have up front to get them installed while the fuselage is opened up during early stages. Battery boxes, solenoids, gascolators, static tubing, brake parts, etc. all can be mounted while access is still good. The engine mount makes a great handle for moving the near completed fuselage.
Have as much available as possible. Sometimes it's nice to have a dumb down day and mount tires while you cogitate.
JMHO
Roberta