Six to eight hours would feel like a long ride indeed for me, but I have been fine up to four hours with Andiamo! padded skins under my running tights. They are about $27 straight from the shop in Hailey, Idaho. The padding is thin, and I think some riders use them as an inner liner inside other cycling shorts. This year my bikes both have the Jones spec saddle which has a bit of padding, so the combination is working just fine for my riding.

I'd probably bring an extra bit of chamois butter and make a stop to reapply halfway through if I were going to ride six to eight hours.

Otto