score:6
I am not sure which sites you have tried, but if you buy your ticket directly from the Danish Railways, you seem to get everything you want:
If you order a seat reservation, you can also select exactly which seat you want. You will be shown a drawing of the carriage, so that you can see where the tables are and which seats are free.
You can have the ticket sent to an e-mail address, or also get a reservation code to pickup your ticket at a DSB ticket counter or one of their ticket machines in Copenhagen.