I found nice inexpensive Sun Screen Fabric at Home Depot in the Garden Section. Although I got it to fabricate sun screen panels for the sides of a 10' X 10' Canopy Tent, it has great potential for us Trailer Sailors.
It is made specifically for permanent outdoor use to block UV and heat from the suns rays. It is very lightweight mesh-like material with small holes for air to pass through.
It comes in three colors - Saddle Tan, Green, and Black with the smallest package a 6' X 20' roll for $35. That's 120 sq. ft. or 13.3 sq. yds at $2.63 per sq. yd.!
One could easily attach small sections to Bimini sides or use a large screen over the entire Bimini which would also serve as a Bug Screen.
capt_nemo