No matter how the APs are configured, there will still be a delay, or hickup, present. You can experience the same thing with the cell phone carriers - especially - I don't know why - if you are moving fast enough, like in a bullet train, when the switch happens, there will be a momentary loss.
When a device is roaming, it goes through three phases:
Scanning: As the device roams and starts to get away from the AP, the Received Signal Strenth Indicator(RSSI) starts to flactuate and go under predefined levels. When this starts to happen the device seeks for alternate APs. After discovering the APs, the device selects the appropriate AP based on the criteria defined on the device itself.
Authentintication: At this stage, your device sends authentication request to it selected in the scanning stage, and waits for either an approval or rejection.
Reassociation: When the new AP authenticates the device, the device sends an reassociation request to newly selected AP. After (if) the new AP approves the request, your device sends a disassociation request to the old AP, so that it is removed from the old AP's tables.
The whole process is known as handoff. Typically, it takes less than half a second. The reason behind the losses longer than half a second is due to the client device's decision mechanic to decide when to drop one AP and switch to another. Some devices have more comprehensive methods to decide when to "roam", others may just stick to RSSI levels dropping below some predefined value.
Therefore, if you are having hickups longer than half a second, I would advise referring to your device's manual or consulting with the manifacturer to see whether the culprid is actually your device. In that case, I would suggest exploring different vendors.