Someone who is great at working with tiny intricate measurements. A smidgineer will get the measurement or angle correct every time.
A smidgician is a master smidgineer. A wizard in his field. A smidgician can eyeball a measurement from across the room and nail it 100 percent of the time.
Wow, you smigineered the f*#k out of that. Your smigineering skills are out of this world. I believe I can smidgineer it in there.