Have you considered to treat each crossing of 360 as a new serie to avoid the draw of the wrap?
float[,] buf1 = new float[13, 2]{
{0.0f, 0.0f},
{30, 0.3f},
{30, 0.9f},
{30, 1.9f},
{120, 2.0f},
{150, 2.1f},
{180, 2.2f},
{210, 2.3f},
{240, 2.3f},
{270, 2.3f},
{300, 2.3f},
{330, 2.3f},
{360, 2.3f},
};
float[,] buf2 = new float[7, 2]{
{0, 2.3f},
{30, 2.0f},
{60, 1.8f},
{90, 1.5f},
{120, 1.1f},
{150, 0.9f},
{180, 0.7f},
};
And make sure drawing parameters are same for both.