I can warn against one thing - if one uses a small brush to lather on face, just parking it in the Large Moss scuttle leaves too much space around it for heat dissipation. So, if you have a small brush and don't want to build lather in / for the scuttle - choose the small one.

One way to alleviate the large Moss scuttle + small brush preference + face lathering combination is to have lather all around the brush, which is something of a waste, I guess... (for me it means that I have to build on the face, and then work the scuttle lather too - and I rarely get to the second part)

Cheers
Ivo