Pretty sure it was 16-bit since the bit rate is 705.6 kbps (mono at 44.1, 16-bit.)
I didn't normalize the file, although doing so would have been a good step. As a practice I don't normalize to 0 dbfs. I prefer to normalize to -6 or even -12 to give myself headroom for proper gain-staging when mixing multiple tracks together (only when working with 24-bit recordings or higher-res soft-synth renderings, though. For 16-bit files I wouldn't go below -6 when normalizing as you are losing resolution by decreasing your dynamic range by doing so.)
From my brief look at R-mix I don't think it will help in your situation that much. R-mix seems best suited to a few very specific noise reduction situations and to filtering between sounds when there is an obvious difference in pitch or the position in the stereo field. Given your recording was in mono that kills one dimension of R-mix's operations right off the bat. I am open to being pleasantly surprised, though.
iZotope RX is a full editor where I can edit any specific time/frequency selection independently of others, so I could select a specific instance of a click and choose from multiple options how best to make it disappear. It's really a much better tool for this job. More of a scalpel, less of a "one-size-fits-all" solution. The downside is that it takes a while to learn its various options and when best to use them, so it takes some experience to move from good results to great ones. It would also make a terrible filter- something R-mix does very well.
Peace,
Tunes