No experience of RX4/6, but use Sony Noise Reduction 'Click and Crackle Removal', set to 'for manually fixing small sections'. The default setting is excellent. I find that, sometimes, it will result in a dulling or hollow quality to the applause. It helps to eq the applause, or even the whole file, to accentuate the applause (visually, make the spikes higher in amplitude) and then run NR. Oddly, and I'm sure there is a reason for this, I've never found this pre-eq necessary on mini-disc recordings, which seem very bright in this range. Hope this helps.