That is strange.  What clearcoat are you using? What type of paint is that?

For large parts you need a mini spray gun, or an airbrush with at least a .5mm needle. Otherwise your spray pattern is much too small.

And with spray cans you have to apply clear in very light coats. And let each coat have a chance to cure at least a little bit. Once you have a couple light coat on and they are nice and tacky, then you can try adding some wet coats.

But the strange thing is your technique worked on the bottom..... Thats weird.