XF 1.5 Twitter Card Related questions

[HSP]

I'm stuck finalizing my Twitter card code, I am applying this in the open_graph_meta template.

<meta name="twitter:card" content="summary" />
    <meta name="twitter:site" content="@YOURTWITTER" />
    <meta name="twitter:title" content="{xen:raw $title}" />
    <meta name="twitter:description" content="Discussion started by {$visitor.username}"/>
    <xen:if is="{$avatar}"><meta name="twitter:image" content="{$avatar}" /><xen:else />
    <meta name="twitter:image" content="{xen:helper fullurl, @ogLogoPath, 1}" /></xen:if>

1. I am unable to get the username of the poster(currently it shows the username of the logged-in user
2. I am unable to get a large version of the avatar. Currently it's medium sized
3. I don't know how to show this meta only in thread views?

 

[HSP]