I now mostly find easy todo missions that offers Modified Embedded Firmware, (grade 5) data, and then use a material trader to trade down to Specialised Legacy Firmware (grade 1) and now you get plenty of this because it is trade down.
So I usually take a look at the mission and look at what the rewards are, and if an easy mission shows up with Grade 5 Material, I take it, and then for the next time I some stuff to trade down with and if you are lucky, the mission you are offered fits in with what you planned todo. I call this opportunistic gameplay, to avoid having to go knee deep (or more) in gathering needed mats for the next engineering task I have planned.