Hi Stardust,
Imho, you need to get your dh to cover for you...as he did in with holding the recent missive from your sister; but then he should have returned it or trashed it instead of expose you to it.
No contact is no contact...zero tolerance...and it sounds like you need this as any mention of her triggers an emotional flooding from which it takes considerable time to detox. It isn't about her or what others think, it is about what you need...and it isn't at all inappropriate to look out for your self, your own mental health.
In going no contact with my sister, I tapered off over 4 or 5 years. The Christmas/birthday gifts that I received, I did send "thank you" notes as sister is a stickler for "properness" (if that's a word)... every thank you note, no matter what was given, was thus:
Dear Sister
"Thank you for the wonderful gift. Your kindness is greatly appreciated."
Me
(It's a form letter
).
(Normally I sign off every letter with "Take care, Love, Me" but I knocked that off and that was that.)
I did return the last bd gift which was our old family movies when we were children (from the 1960s and 70s) put onto DVDs. I did not watch them. My other sister said that only about two min. of visible images transferred as the film was badly deteriorated.
This was a 'first installment, she would send more as she had them done'.
I felt it necessary to return them and let her know I was not interested in them-so she would not make anymore on my behalf. My counselor said it was a manipulation to show me as a child again-so she could be superior and treat me like that; and also, a "look what I have done" kind of show off.
Imho, making announcements to her beyond what you have already said is a waste of time. Just operate on the action of a mature person who has set the boundary...that toxic sister doesn't get it or won't get it makes her look the pathetic, immature one whose brain can not evolve as you patiently cast off her offerings (she is like a cat bringing a dead bird to you).