I don't think its a bad idea to set a knot at any level. If its a loft you really enjoy, than there's no problem. The loft of a shaving brush is all personnel preference. I have a 20mm, 2 band shave brush I set at a 48mm loft, and I think that's the perfect loft for that knot. I also have a 20mm black badger with a 54mm loft, and it works well too. My advice is to try the loft at many different levels and see what you like. It's all personnel preference when it comes to this. There's no right or wrong answer here.