Try converting your AVCHD footage to XDCAM EX using the free MPEG Streamclip. The EX codec will make files that look as good as the ProRes FCP will trancode your AVCHD files to and they will be much smaller files on your HD. Here’s a tutorial video that talks about files from the Canon 5D Mark II, but your HG10 files should work the same. Make sure to then use the XDCAM EX Easy Setup in FCP to set your FCP Sequence for editing:
https://www.videosurf.com/video/how-to-convert-5d-mark-ii-h-264-footage-to-x...
Here’s where to get MPEG Streamclip freeware: https://www.squared5.com/
Reid VanVoris
e-Mail: r1108@hotmail.com