I absolutely love Buxton, which I find works well for prints of any size. Herschel (also from Ruscombe Mill) is very good too - slightly less white, more textured and a touch slower than Buxton; it looks great after being hot pressed. As far as I'm aware these two are the only papers available that can be used to make decent pure platinum prints without any pre-treatment (I could be wrong and would love to hear about others).