GH4 footage render settings in Sony Vegas
Vimeo recommends uploading with frame rates of 24 (or 23.976), 25, and 30 (or 29.97). If your footage exceeds 30 FPS (frames per second), you should encode your video at half that frame rate. For example, if you shot at 60 FPS, you should encode your final video at 30 FPS.
If your video editing software gives you the option, choose a “variable” bit rate and set the target to at least 2,000 kbit/s for standard definition (SD) video; 5,000 kbit/s for 720p HD video; or 10,000 kbit/s for 1080p HD video.
BTW, if you have troubles in importing & editing GH4 footage in Sony Vegas, you can refer to How to edit Panasonic GH4 4K MOV/MP4 in Sony Vegas.