[klondike98]

you can always use a cap that is rated at a higher voltage and conveniently they sell film caps rated at 600 or 630v for all the caps that are less than 1uF.

I buy them at Just Radios but there are other places as folks have said. Just Radios has some nice tutorial info as well, for example: http://www.justradios.com/captips.html
and the info on safety caps: http://www.justradios.com/safetytips.html

The two 0.01uF caps labelled as #81 on the Riders schematic should each be a Y2 safety capacitor.

The 8-12-16 uF electrolytics (cap #21) will likely have to be purchased as 3 separate electrolytics and then wired in or it may be possible to stuff them into the existing can after it has been gutted. (I've not worked on a 41-608 so I'm not sure how big that can is). I also don't know the voltage rating for these so you either need to get that info off the existing cap or perhaps someone else here can offer a voltage rating suggestion.

I don't know about the 100uF cap either, I don't see it on the schematic.(if you are looking at cap#58...that is a 100uuF or 100 pF cap...and probably does not need replacing)