This is my understanding as well. In the film, Red 1 pyro is obviously used per this thread, and Red 4 seems to have a better quality miniature for its explosion as well. Red 3, 6, and 10 are really cheap looking miniatures - with no engines, simple sticks for cannons and even the wrong wings. I think they were made out of scraps from earlier explosions.
The same can be said for the Y wing explosions - Gold Leader and Gold 2 are relatively cheap looking, Gold 5 is one of the top grade pyros, known as "4 triangles".
There is documented interview material about the explosions and the trial and error for same, but a behind the scenes story I've never heard is the tale of the pyro miniatures themselves.