I assume you've checked to see if the stop solenoid is picking up, if not,
step one: take jumper lead from positive terminal to stop solenoid terminal, (click = working solenoid)
step two: turn key to on position, repeat step one (click = ignition switch circuit not working)
I assume you didn't obliterate what compression you had, by beating the everliving piss out of the engine.
test glow plugs?
take a DC ammeter, and place your + lead to positive on battery, and - or ground (however your meter is setup) to glow plug bus bar. warning: some meters have multiple load settings, make sure this is set to the smallest setting OVER 50 AMPS
Your meter will complete the circuit, bypassing the relay, fuses, and wiring.
I don't recall glow plug current values independently, but I believe they are approx 12-15 amps each. so a reading below 50-60 amps would indicate at least one GP is bad. bad GP = hard starting.