Based on suggestions from other builders, I will be using rivet nuts in certain situations; to make the trans tunnel removable is one instance. I ordered aluminum rivet nuts from McMaster Carr. My issue/question has to do with the screws. I can't seem to find screws that are made of aluminum in the thread size I intend to use; 6-32. There are plenty of stainless steel, brass, zinc, etc. I've read that using mixed metals can cause "galvanic corrosion" yet I've read on the forum where many used stainless screws on their removable trans cover so I'm confused. Should I mix metals i.e. stainless and aluminum? If not, is there another option instead of aluminum screws that I can use with aluminum panels?