I buy disney gift cards and use them throughout the trip. You can manage the gift cards on the DisneyGiftCard website. It is easy to transfer an e-gift card amount to a physical gift card. I would transfer the amounts as needed to the physical gift card. The $500 amount does have to be transferred in total, you cannot transfer in different monetary increments, for example, $100 dollars from the $500 e gift card to the physical $100 card - does this make sense. If you are staying on-site at a Disney owned resort, you can charge to the magic band and just go to the front desk to apply the amount to your account. It is easy to track spending with the
MDE app, so when I get to a certain amount - I go to the desk to pay off with the gift card -- just remember to do this frequently and at least 24 hours before check out.
Hope this helps! I like using the Target discount to save money on a Disney Vacation -- every bit helps!
Have a magical time.