I think

myCustomers.Width = Unit.Percentage(100);
myCustomers.GridLines = GridLines.Horizontal;
myCustomers.HeaderStyle.CssClass = "ms-vh1";
myCustomers.CellPadding = 1;
myCustomers.BorderWidth = Unit.Pixel(3);
myCustomers.HeaderStyle.Font.Bold = true;
myCustomers.HeaderStyle.HorizontalAlign = HorizontalAlign.Left;

should be (that is bolded)

myCustomers.Width = Unit.Percentage(100);
myCustomers.GridLines = GridLines.Horizontal;
myCustomers.HeaderStyle.CssClass = "ms-vh1";
myCustomers.CellPadding = 1;
myCustomers.BorderWidth = Unit.Pixel(3);
myCustomers.HeaderStyle.Font.Bold = true;
myCustomers.HeaderStyle.HorizontalAlign = HorizontalAlign.Left;