Prefill field based on NextGEN Download selection

I am trying to DIY a NextGEN Gallery proofing solution. You can see what I've done so far here: http://scottwyden.com/proofing/example/

I was thinking one way to do it is to have a Gravity Form take care of the Download Selected Images button and also email a list of selected images to me.

Here is the code that drives the download part of the template:

[php]
<!-- Thumbnails -->
	<form action="<?php echo admin_url('admin-ajax.php'); ?>" method="get" id="ngg-download-frm">
		<input type="hidden" name="action" value="ngg-download-gallery-zip" />
		<input type="hidden" name="gallery" value="<?php echo htmlspecialchars($gallery->title); ?>" />

		<?php foreach ( $images as $image ) : ?>

		<div id="ngg-image-<?php echo $image->pid ?>" class="ngg-gallery-thumbnail-box" <?php echo $image->style ?> >
			<div class="ngg-gallery-thumbnail" >
				<a>imageURL ?>" title="<?php echo htmlspecialchars($image->description) ?>" <?php echo $image->thumbcode ?> >
					<?php if ( !$image->hidden ) { ?>
					<img title="<?php echo htmlspecialchars($image->alttext) ?>" alt="<?php echo htmlspecialchars($image->alttext) ?>" src="<?php echo $image->thumbnailURL ?>" <?php echo $image->size ?> />
					<?php } ?>
				</a>
				<label class="proof_download">Download<input type="checkbox" name="pid[]" value="<?php echo $image->pid ?>" /><span><h4><?php echo htmlspecialchars($image->alttext) ?></span></label></h4>
			</div>
		</div>

I used http://wordpress.org/extend/plugins/nextgen-download-gallery/ to actually handle the downloads. Do you think it's possible to have GF's submit button handle trigger the download? And if so, do you think it is also possible to have a paragraph block pre-fill with the file numbers?

Thanks for the help!