As long as they are installed properly they should not warp, but yes there will be expansion with the high heat. For asphalt liners we usually...
A plastic liner would probably help. If you want some information or specifics I can try and answer your questions in this thread. Can get them...
The plastic used is UHMW Polyethylene. The plastic is made in sheets and has to be welded together to make one large continuous piece. There have...
If you have access to ratcheting cargo jacks / load bars those help getting it pushed donw into the corners.
You wouldn't need to go with a Quicksilver liner for what you are hauling. It would be overkill. You could probably get by with 3/8" HMW liner...