I use InstaDebit too and I agree they are much faster than Neteller. Unfortunately, the casinos I prefer don't take Instadebit. I never fund my Neteller or Instadebit accounts. I always let the merchant pay my fees. They are going to take most of my money in the long run so they should pay for the privilege.
Also, many casinos won't send my withdrawals to InstaDebit even if I used them to fund my account. One casino tried to send a part of my withdrawal to InstaDebit and it has never been found. Still working on it.