One more question regarding matching the sampling rate of my zoom to the camera for later synching: the audio sampling rate of the camera is not stated anywhere in KHz units. It's a Panasonic HC-VX870 and the audio spec is "AVCHD: Dolby Audio (5.1ch / 2ch)" and the mic spec is "5.1ch Surround, Zoom, Focus and Stereo Microphone". Would this be 48KHz?
Yes the broadcast sample rate for cameras is 48khz. Increasing the Zoom rate to 48khz to match is slightly improving the frequency response.