I had to Google 'took a powder' to understand what you meant. For others as unaware of American slang like myself, it means they disappeared.
It depends on what you are looking for when you test.
yDNA testing will give you information about your father's father's father's etc DNA.
https://isogg.org/wiki/Y_chromosome_DNA_testsThis will obviously only apply to your paternal grandfather, providing that you are a male, or can find a male from the same line to test (brother, father, paternal uncle). It will give you no information about your maternal grandfather at all.
The autosomal test which you, your sister and maternal aunt have had done, will give you information about both your grandfathers.
If you are hoping to find out if you have any half aunts or uncles from 2nd relationships your grandfathers may have had, it will be a question of waiting to see who has tested and looking for close matches that you have never heard of before.
If you are hoping to find out about your grandfathers' ancestors, there again, it will be a question of sorting through your matches, perhaps following Lost Cousins DNA masterclass techniques.
https://www.lostcousins.com/newsletters2/aug17news.htm#MasterclassIf you can persuade a
paternal uncle to test as well, you will have representatives from both paternal and maternal lines, should help you decide which side of your tree your many thousands of matches are from.
Use shared matches as much as possible.
FWIW I have 2 brothers, neither of whom have shown an interest in DNA testing. If I was feeling generous, I would pay for them to have autosomal tests, would not consider paying for them to have yDNA tests.
Regards Margaret