Does HubSpot has the option (somewhere) to create white space after your desired email preview text so that email clients don’t pull other distracting text or characters into the envelope content?
I'd like to add a chain of zero-width non-joiners (‌) and non-breaking spaces ( ) after the preview text that I want displayed. The repetition of “‌ ” would then fill any remaining preview text space.
Where could this be added in the HTML of the email to enable this to work?
You can maybe try to add the smallest widht possible (0.01 I think) because I am not sure you'd be able to add a width = 0. I would also suggest to you to take a look at this article here.
Also you can have a look on the preview code showed here on the #email anchor.