I’m between 3 typefaces
Optima: because it’s a humanist typeface and makes a contrast to the simple, mechanic/structural logo.
Gill Sans: a classic modernist typeface and I think it suits to the logo
Futura: its geometric and simple aesthetic suits to the logo.
I placed the versions in order of ‘boldness’. Maybe I can adopt the use of both Optima and Futura as they don’t look so much similar.