How to write a custom Renderer for Bindable Picker to change its Font attributes: Family,Size ?

Hi,
I am using a BindablePicker as given here . However, the displayed selected item name font size by default is larger than what is required in my design. So, I want to add two more properties to this picker so that the displayed text, which happens to be the DisplayMemberPath can have desired font size and font family.

I have added them in the BindablePicker control as :

public static readonly BindableProperty FontFamilyProperty =          
        BindableProperty.Create("FontFamily", typeof(string), typeof(BindablePicker),string.Empty,BindingMode.OneWay);

        public string FontFamily
        {
            get
            {
                return (string)GetValue(FontFamilyProperty);
            }
            set
            {
                SetValue(FontFamilyProperty, value);
            }
        }

        public static readonly BindableProperty FontSizeProperty =
               BindableProperty.Create("FontSize",
                   typeof(float),
                   typeof(BindablePicker),15f);

        public float FontSize
        {
            get
            {
                return (float)this.GetValue(FontSizeProperty);
            }
            set
            {
                this.SetValue(FontSizeProperty, value);
            }
        }

How do I write an android and an iOS renderer to achieve the requirement ?

Related to this issue,
I just tried setting the control's font size and family in the renderer (not as mentioned in the XAML, but hard coded) as :

Android:

protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Picker> e)
        {

            base.OnElementChanged(e);
            if (Control != null)
            {
                Control.Typeface = Typeface.CreateFromAsset(Context.Assets, "Roboto-Medium.ttf");
                Control.TextSize = 16;
        }
}

iOS:

     protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Picker> e)
            {

                base.OnElementChanged(e);
                if (Control != null)
                {
                    Control.Font = UIFont.SystemFontOfSize(16);
                    Control.Font = UIFont.FromName("Roboto-Regular", 16f);
                }
    }

This although creates not much of an issue in iOS, the pop-up dialog displayed in the Android device is not proper.
I have attached the android screenshots here.

I want the picker pop up to be as the default pop up, but the font size and family set as in the custom renderer.

How can I achieve this ?

Any help would be greatly appreciated.