Rosedanny, 45's like 33 1/3 rd's are not created equal and your observation regarding the lack of discernible difference between the two "Claire de Lune" pressings is not surprising. I had a copy of Classic Records 200 gram 45 rpm release of Norah Jones "come away with me" (notice I used the past tense) and it was inferior in every way to a relatively inexpensive European 33 1/3 pressing. That being said most of the 45's I have sound fantastic and for each of the few I have for which there is a duplicate 33 1/3 LP in my collection, the 45 version does sound superior. There are still, however some really special 33 1/3 that blow away some of my 45's.
45 vs 33.3 RPM
Forgive me if this has been discussed. What is the line of reasoning behind reissuing records at 45 rpm, which were originally cut at 33.3? I have a Classic Records reissue of the Living Stereo "Claire de Lune" album, and can't hear a difference between it and the original I have at 33.3.