Hexagonal grid with 120 degree angles

How to set grid cell size for regular hexagons (I am using Unity Tilemap and Grid components)? I mean hexagon with 120 degree angles (regular hexagon). If I have cell height = 1 unit then width should be = sqrt(3) * width / 2 (for point top hexagon). I can't set right cell width in inspector because of sqrt. Even if I set it manually, but it is not elegant solution. If I rotate the grid for 30 degrees, I want to get the same hexagon, but I get crooked one (with default cell size).