la crosse iowa minnesota

So I bought a 2010 TDub, and I already have the itch to do some add ons, My questions are... 1. Can I attatch the Rotopax attatchment to the immix cargo rack I ordered? 2. What is a good brand waterproof bag to strap down on top of Rotopax fuel tank and immix rack? (I don't want a hard...