Lua spy is garbage. It's a pain to do and takes far too long.Ugh, one of the Lua Spy puzzles is awful. The jump-latching one.
As per chat advice, I guess I'll get Ivara before I farm Lua Spy. Plus, Spy missions seem to be the best way to level the Mote Amp, so I can take down the Stalker when I'm on a low-level warframe and/or levelling weapons and/or on too vulnerable a warframe.