I'm glad that worked out for you.
I'm not quite clear on your question in regard to return size, but hopefully these generic response will help.
Anytime a new variable is created in an extension, the new property and value is added to the UDO which increases the size of the object. But that doesn't mean the value is passed to a tag, it's just available to be passed to a tag.
If you are asking about the size of utag.js being bigger which refers to the load time in the browser, then anything configured in the Tags, Load Rules, and Extensions tabs are output to the utag files. Therefore this will increase the size of what is being loaded into the browser.
Let me know if this helps answer your question.
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