Lag or slow response time from your gimbal can result from several factors.
Low Gain Setting
Raise the gain on your HoverflyGIMBAL by steps until the lag is no longer noticeable.
If your gimbal begins to jitter or over-correct, you have raised the gain too much. Please see this article:
In some cases, the lag you experience from your gimbal may be the result of your servos being slow or overburdened. Please attempt the following:
1. With no load on the gimbal, connect your servo directly to your receiver (with power to both).
2. Move the stick on your transmitter from one extreme to the other and note the speed with which the servo reacts. If it is still slow to respond even without a load, you may need faster servos.
3. If the gimbal reacts as expected, repeat steps 1. and 2. with the camera attached to the gimbal. If the gimbal reacts slowly with a load attached, you may need more powerful servos to move that particular camera.