Dynamically Populate 3rd Party Form From Gravity Form Submission

So I have read many posts about dynamically populating fields from GForm to GForm, but I am trying to transfer values from a GForm to a WooCommerce checkout form.

I have done this:
http://www.gravityhelp.com/documentation/page/File:Form-settings-confirmation-redirect.png

which gets me the values passed from the first page with the gravity form to the WooCommerce checkout page. Now I need the WooCommerce fields to grab the values.

I made a simple edit to the woocomerce form array so that I can use a hooked in filter like this:

// Hook in
add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

// hooked in function - $fields is passed via the filter
function custom_override_checkout_fields( $fields ) {
     $fields['billing']['billing_email']['value'] = $value;

     return $fields;
}

So, I have data passed via a query string, a function hook, which can post data to the 2nd form... now how can I link the two? I feel like I'm close, but I could be miles away.

Is it possible instead to save out a session variable such as:

$_POST['email_address'];

I could use that in the hook filter for woocommerce.

Any help would be HUGELY appreciated! Thanks!

Perfect! Thats exactly what I needed.

Thanks!