Re: A4 vs. A5
A4's have a more or less balanced EQ, no big push in any direction, so to players that are used to that, A4's can seem bland. But less coloring also means that more of the PU's and wood's tone may come thru.
A4's won't have a boomy low end, or sharp highs. The bass in an A5 is tight, but because ther's so much of it, that abundance can sometimes be an overdose and make it sound loose.
A RC A5 will take off a little of the high and maybe a bit of the lows of a polished A5. A3's have almost as much treble as an A5, but they also have some mids and not much bass; won't have any boominess with them.