[Zedn]

That's how it is for all metallic base coats. They need to be off the gun before clear. If you sand it will see bad marks. You can usually knock off any nibs then retouch those areas before clear.

If you are doing it in your garage, you really just want to get plenty of clear on there and then wet sand the whole car up to the finest sandpaper you can find and then buff it with a cutting compound followed by a finer grade polish.