I bought an SV45TE on eBay, and the bellows are pretty stiff compared to a friend's well used SV45. I think they are quite probably too stiff to squeeze tight if using something like a 75mm lens (though I haven't tried this).
It was suggested that I leather feed the bellows to soften them up, but when I asked the retailer what to use, they weren't so keen on the idea at all!
Do many of you feed your Ebony bellows, and if so what do you use?
Looking at the bellows, they seem to be material on the inside and maybe leather on the outside (though they don't smell of leather particularly, so possible there is a protective coating or something). They are the original bellows (so I'm assured and they look original) but just not been used very much at all.