For the inside miter, we recommend using our High Flow Inside Miter Kit.
The kit comes with LeafBlaster Pro 14 Mesh for the high flow areas. Slide one piece all the way to the back corner. When joining the adjacent piece, trim the aluminum ends to leave exposed mesh. Tuck the exposed mesh down inside the gutter adjacent to the adjoining gutter guard.
Use the kit’s Rainwater Diverter if overflow is occurring at roof valleys (or other high flow areas) to help to disperse rainwater over a wider area. Trim the Diverter to closely match the shape of the base of the roof valley. Once trimmed, bend the diverter to shape and slide it under the shingle just above the gutter guard.