So far for the real rubber I am using bike inner tube rubber. I think it will look the most real when i am done. As for size... yes it is huge, by far the biggest project I have ever done. The hard part is the lack of real good reference material. I have tons of pics from the web, but only pictures so far no other info except the basic dimensions. I have added the other vehicles to help me get some reference in size when building the final ship, also the LCAC usually carries a full load of military equipment. Along with the LCAC I am currently building 3 other vehicles to go with it ( M-923 A1 5T truck, LAV-25 TUA, M998 HMMWV Hummer ), with plans of more vehicles to fill up the deck. I have my hands full in taking on this project but I have been happy with my results so far, and I like the challenge of building something that has not been done yet, Aloha