Today I discovered a fantastic brush for doping.  It is far and above any camel hair I have ever used.  I bought it at a local art supply about 10 years ago, but used it for the first time today.  It is a Winsor & Newton, Series 140, goat hair wash brush.   It is a full dense brush and the hairs are very fine.  When you dip it to load up, it holds at least 50% more than the same size camel hair brush.   Also the dope flows out to the surface much smoother,  I think its due to it different shape than the camel hair dope brushes I've been using.  Instead of the hairs all being the same length, they are cut to soft taper and it leaves no edges on either side of the brush line.   I'm using the 3/4, they also come in 5/8 and 7/8.   I have already ordered one each of the other 2 sizes and will check to see if other brands have smaller sizes of same type.  They are around $7 from internet sites, probably $10~$12 from local art supplies. The 3/4" is a W&N #5240002.  Dont know why but it even seems easier to clean..