What do you do to stop the Sprig from fraying outwards when drying? Only my Sprig does it, but my regular Monarch Elite XL's don't suffer from this.
I don't have a problem with substantial fraying.
With respect, it may be a function of the way the you wash and dry your brush.
I start off by holding the brush under a tap. If the water based paint has started to cling to the bristles, I gently rub the long side of the brush against the palm of my hand. I do both sides and rinse the brush again to ensure that the clingy paint has been dislodged.
I then fill up the basin with warm water and gently push the brush up and down (at an angle so that the bristles bend uniformly in the same direction) until the water coming out of the brush is clean, often, that requires a number of basin water changes. I don't stab the brush in the water, I bend the bristles front to back, along the length rather than side to side.
When removing the excess water from the brush, I take it outside and flick it along the thin side, in both directions (rather than the long side). I then use my hand to pull the bristles flat. I will from time to time, leave it sitting on a radiator to dry but I only leave the wooden handle on the rad. I don't want direct heat to dry it.
Years ago, I purchased a spinning tool to remove the excess water from brushes. That seriously splayed bushes...