I had an experience with NAPA drums. Van would shake from 45mph and up.
I tried many things, moving tires around.....having all 4 tires spin ballanced.......checking this and that.
Finally, I re-installed the old drums and all was fine.
So in my particular case, the new drums were out of ballance.
SO......maybe try putting the old drums back on.....see if it changes anything.
The least you will do is eliminate the drums as the cause of your problem.
A slightly out of round drum could sure cause your problem.
Another thing to check....make sure that the seating area on the hub is smooth....that some rust bump is not making them slightly not true when they seat.