waterproof car cover for a 64 barracuda

I have all the body parts to fix this except for the aluminum rocker panel sill plate. Laysons has it on back order. After they pull the hinge pillar and rocker panel out on the frame machine... they said we may need to have a rocker panel and hinge pillar cut form a junk yard donor car. Then cut the old one out and weld the new part back in. It's a small restoration shop with limited space, so it would be outside until the parts come in from the junk yard. probably 2 weeks max.
I did buy a sealskin cover, last week, hopefully it will do the job for the 2 weeks