This is right on the money. ^^^^
An Envy knot for instance, which is one of the denser knots you can buy by itself, set into a 26mm opening is going to feel almost like a 28. 
Here are two brushes with the same 24 mm Envy knot, set to a mm's difference in free loft, but the Doug Korn has a smaller opening, and the Nathan Clark is right about at a 26.
![[IMG]](proxy.php?image=https%3A%2F%2Fuploads.tapatalk-cdn.com%2F20170422%2F8e3ce9affbbd1bd119d34d082523ab58.jpg&hash=1df336c590b2dbb27872e3f61fdf6fb8) 
![[IMG]](proxy.php?image=https%3A%2F%2Fuploads.tapatalk-cdn.com%2F20170422%2Fe4530b11caf8c50cf38b8441250fcbbd.jpg&hash=36be4ef507ce6c326aed70e697d4e193) 
Two completely different brushes; both just excellent. The one on the right definitely feels like a bigger brush though.
If a guy didn't want to drop that much ($60 ish) into a knot, I would look at a TGN 2 band finest. A similar knot, just a little less dense, and probably a little less soft. Still really good knots though. I have several, and wouldn't hesitate to buy more.
If you want Silvertip, I would again recommend looking at TGN. 
@Douglas Carey has one in grade A and has spoken highly of it. It was recommended to him by @Boojum.  If either one of them recommends a knot, you can take that straight to the bank. 

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