@bistrodiner. First Welcome.
1. When you say "slanted" in my opinion you want to say high relief. This could happened in the process of the die production. Been a variety? I have to see some studies on this subject. I have around 10 mint circulation rolls for this year, but unopened. If I will not see al least one major variety discovered or more then 3 errors strike I will not open. Keep for who want to studies this year strike.
1a. Slanted is use more to a deviation in the design which meat at least 10 degrees deviation from the axe. In fact we say: die rotation. This die rotation was almost eliminated in 2005 when the mint adopted two different guides for the anvil and hammer die. The actual permitted tolerance for alignment of the anvil and hammer die is 0.5 degrees. Also understand that now and also that year the strikes was horizontal and not vertical, which eliminated those floor rebound and angles deplanements.
Hope at your convenience.
2. Please take look at the difference at the weight. Happened also that a planchet (better say) the roll which was prepared for the mint, to be more or less on the requested parameters. Also the head and the end of the rolls have thickness differences.
Those who look and categorize the errors and varieties will decide. For me interesting is what cause those anomalies.
Again welcome and good luck.
Silvio