Those sent domestically had two 400d Tran Hung Dao stamps.
12 sets were mailed within Vietnam.
Those sent internationally had one 400d Tran Hung Dao stamp
plus additional postage according to the destination (USA or Australia).
11 sets were mailed to USA.
I can't thank my "dear little sister" Dieu enough for her help with this project. I don't think I could have completed it without her. She ensured that I
had enough of the 838 stamps available, helped me locate addresses, collected extra sets that I mailed to myself in Vietnam, and shipped them to me.