#8, #57, and #304 are all top coats IMO
#2's and #4's are base material.
#8's are 1/4" -1/2" stuff. Common for alot of driveways. In the "gravel" variety, it is the size they use in asphalt.
#57's are ~3/4". Also common in driveways. Especially for heavier traffic or heavier equipment.
#304's have a few names. Crusher run, 3/4 minus, etc. It is just a mixture of gravel down to dust with nothing larger than 3/4". Creates a nice smooth topcoat, but does get kinda muddy on top when wet. That limeston dust sticks to your boots and tracks everywhere.
So you have to decide on what kind of top coat you want.
But for base, #2's are bigger. 2"-3" stuff. And #4's are ~1"-2.5" or so. And can very by reigon but some places have mixes fo bases that may include #2's AND #4's.
But either way, you need a base of #2, or #4's or whatever you choose. THen do the topcoat. What you are looking at now is both top coats, and arent the best for bases.