If you’re building a wallet for your token and you decide to be a delegate you can do the following
1. Accept fields and generate transaction signatures from the UI. Store them in a DB (or maybe even a slightly more decentralized datastore)
2. After storing the signature, execute it from your central admin account which you own which has a large ether balance. You will probably have to code and configure this part.
If you’re not the token admin, the best possible scenario is to have an open marketplace where all ERC865 tokens can get executed. However, the token will require a high demand and high volumes to have execution speeds which are instantaneous.