Les Pauls tend to have really fat bass and strong clear treble naturally because of their wood/construction. They don't emphasize mids. Putting in pickups like the Custom5 and 59n which also emphasize the bass and treble while lacking mids is too much of a good thing. A Les paul needs pickups that don't get boomy in the bass and have a good helping of mids to fill out what the LP lacks. A2 pickups and some A5 pickups like the Whole Lottas, which have more mids, work better in Les Pauls. An SG, which has more natural mids is where you want to put the Custom5 and 59n.