The ideal brush isn't too big nor too small. You want to be selective on where you are placing the product, so the face isn't overwhelmed with shine. It is up to you if you prefer an angled brush or not. I personally love them. My two best suggestions are:
1. Sephora Collection Pro Blush Brush #49
2. Sephora Collection Classic The Complexion Brush #53 if you prefer a rounded brush
Also, If you are ever looking for a perfect highlighter, I LOVE Dior Diorskin Shimmer Star in Amber Diamond.