Not having a personal twitch channel, I don't have an opportunity to see these messages. But from your description, it sounds like your issue is that someon giving 10 gifts causes there to be 10 separate messages, and you want to have them combined into just 1 message?

It's easier if you can see some debug messages showing exactly what messages are received in that 'raw USERMODE'. You can make it create some debug messages by insert these commands immediately below the 'raw usernotice' row:

Code
if (!$window(@usernotice)) window -z @ @usernotice
echo 3 -t @usernotice nick $nick chan $chan tags: $msgtags
echo 4 -t @usernotice nick mesg: $1-

Once you see what the messages look like, you'll have a better idea how to handle them.