I've read great things about the 177 and the D01. I've used a 177 that was far too big and a D01 that was too small so I don't know have a proper reference point on either. I've heard that the ideal Shavemac is a 23mm knot with a 50mm loft. I'm pretty sure that I could custom order either to those specs but I'm hoping there is someone who has played with both that could tell me which route to explore. I don't face lather as my neck is very sensitive but I don't have any issue with the increased backbone of the D01 that I've used. I did send the fine folks at Shavemac an email in regard to this a week ago but I have yet to hear back.