You described it correctly, except that my Nova had 16-bit word and content was displayed by 16 lamps (tiny bulbs - it was before LEDs). Scope 'terminal' was something minicomputers of that time could not afford. But few hundred instructions for a papertape loader is much - my bootstrap had 20-30 16-bit words.

Which was that machine your dad worked on? 6 bit word could be something from Remington Rand (later Sperry, then Univac, then Unisys).