Missiles come off the bench in pairs, and every pair eats a piece of tech trash. Sulfur hardly matters here; the tech trash is what your C4 wanted too.
The bench hands out these missiles in pairs, and every pair costs one piece of tech trash. That is the part to count. Tech trash cannot be crafted at all, so it comes from monument crates and from electronics you recycle, like a spare CCTV camera or targeting computer. Each piece spent here is half a C4 that never gets made.
Research comes in two parts, both at a Level 2 bench: the missile and the homing missile launcher that fires it. The launcher is the slow one, because its recipe also wants a CCTV camera, which no bench can craft. Wait until that camera sits in your box before you learn the missile.
Watch out
Don't craft a stack on spec. Recycled missiles return tech trash only now and then, so a box of them with no launcher is tech trash locked away.
For anything on the ground, a high velocity rocket costs a pipe and no tech trash at all.
Questions
Homing Missile ×10: how many resources?
Sulfur ×1,000, Charcoal ×1,500, Metal Pipe ×10, Tech Trash ×5.
Which workbench does Homing Missile need?
Workbench level 2.
How long does Homing Missile take to craft?
25 s for one, every step included.
How much scrap does researching Homing Missile take?