Bolt Material for Securing Frame to C Channel

[mystereons41]

Hi all,

We're in the process of replacing some rotted subfloor in the front section of our 1988 34' Limited Airstream. When we replace the bolts that secure the frame to the C channel, what is the best material?

I read a some people were using stainless steel, but looking at a galvanic corrosion chart (attached), it says that aluminum and stainless are not a good match. The aluminum will supposedly sacrifice itself to the stainless steel.

On the other hand galvanized steel to mild steel (I think the frame is mild steel??) is also showing up as a bad match on the chart.

So not really sure what the best option is.

Suggestions?

Thanks!