IIRC, its instruction set supported words (36 bits), half words (18 bits), third words (12 bits), quad words (9 bits), and sixth words (6 bits).

For characters, 6 bits also was used at times, for example in its disk format. There, a severely limited character set wasn’t problematic.

The later versions (1100/60 and later) had loadable microcode. This allowed for some pretty nifty emulation options.

> quad words

Shouldn't that be quarter words? Quad means quadruple.