Ramps on big rings are specially configured for combinations: 50/34, 52/36, 52/38, 53/39T.
Remember when selecting your chainring sizes - it's not about what others use, but about ensuring YOUR ability to maintain a comfortable and effective cadence across the terrain you ride most often. If you ride chainrings that are too large (round or oval), your cadence will be lower. This can affect your performance by prematurely tiring your legs and possibly lead to stress injury in your knee joints.
Most CX riders choose 38T as most versatile option. If you feel strong try bigger size.