Here's the embed code. It has width parameters, but none for the height, as far as I can tell:
<a name="form75036628" id="formAnchor75036628"></a>
<script src="https://fs21.formsite.com/include/form/embedManager.js?75036628"></script>
<script>
EmbedManager.embed({
key: "https://fs21.formsite.com/res/showFormEmbed?EParam=m_OmK8apOTDa00yXoWS-q4tnCkg3VqvK&75036628",
width: "100%"
});
</script>