[Arran]

I know that some say that using larger value caps is hard on the rectifier tube but I haven't really noticed whether they wear out quicker or not. In the clock radio next to my bed I used a pair of 160 mf photoflash capacitors and it's been in use for years. The 35W4 rectifier tube did die but it was because the 50C5 was loose in it's socket and making intermittent contact, but it was playing for at least 3 hours a day for 5 years prior to that. In this case they used a 25 volt cap in place of a 450 volt one so the capacity is really a moot point.
Regards
Arran