Simple tool made of odd bits in the workshop. It could be developed / improved further. It is in three parts:-
Pt.1. Tube 3" long 3/8" o/d Threaded 1/4" bsf Peg welded on one end.
Pt.2. Rod 5" long 5mm (approx o/d) End suitably bent to form peg at one end.
Pt.3. Screw 3" long threaded 1/4" bsf.
Operation....
Place rod in tube and pegs in loops in spring ends.
Fit screw and wind in to push pegs apart.
Hook springs on to shoes, remove 'spring fitter'.
Obviously this cannot be used on the earlier shoes where the springs do not have the necessary loops.