Another vote for charge saddles.
I've done two 24 hour solos on my current one and not had to resort to two pairs of padded shorts (at the same time) in either race. That settles it for me.
If you want more convincing:
They#re probably just a rebaged cheapo generic saddle but they come in a nice range of colours, aren't particularly heavy (I think, not actually checked…), are ridiculously cheap (£20 – cheap enough to try without worrying if you're going to like it or not) and are, for me, very comfy.
Better than the flites I used to use, way better than the soggy mess SDG saddles turn into in the wet and much better than Spesh's BG stuff. Awesome.