Help with rusty sills

[Ro55H]

My car is at a body shop at the moment getting the sills redone to try and remove as much rust as possible and then plate them back up. I believe there is some drainage holes that run through the sills and then drain out the bottom of them, and i was wondering is there anyway of diverting them so they dont run through the sills, or if there is any modifications that can be done to help with the drainage. Also would filling them with waxoyl help or does it just clog the drainage holes up? They are a daft idea from what i can make out, because the sitting water inside them means they rot from the inside, ive been told by the body shop that they cant put any guarantee on the job and they could be rotting back through again within a couple of years.

Ross

[Ro55H]

I went to see my car at the body shop today, and it seems the sills are just starting to rust on the inside, would you recommend putting full new sills on, or just having them repaired and putting some sort of rust treatment on the existing ones, i forgot to take some pics, will get some on here asap. The guy at the body shop said that if he plates it up, it will only be temporary as the rust will now set in, the only rust that was visable was bubbling on the join but now it has been opened up you can see surface rust on inside of sill. They are solid apart from the surface rust, so i dont really know what to do.

Ross