So what I have now is a decent AVCHD update on bitrate (HD and FHD) and no change to stock MP4 files. Further reading at personal-view.com shows that MP4 bitrates over 23M/sec will not allow playback in the camera, so we'll stay at 20M. Other setings that were discussed did not provide enough reason for boosting audio as that will also 'break' GX1 playback.
I attempted to run ten-second snips at each setting to determine bitrates - but I was shooting at max ISO (3200) at our table so nothing special at all. No movement other than cats cleaning themselves, so nothing worth inspecting for difficult imaging like the website suggests to show the improvements that AVCHD should demonstrate. I'll head down the hill for some moving water in the near future, as blockiness of moving water is a known torture test. I'll be happy if I see a minimal amount of frozen pixels in the moving water during playback. The hack settings suggest much larger bitrates than I am trying, so if some image breakup occurs I can bump these up more; I went with about half of their suggested boosts for both 1080 and 720 resolutions in AVC mode.
Here are the resulting file sizes, which did not quite align at 10 seconds. Clearly the MP4 files are smaller as expected. The stock GX1 settings for AVC are 16M/sec and 12M/sec but I bumped them up to about 32M and 20M (or thereabouts). Perhaps at some point I will re-hack at higher AVC rates, but until I see some results to justify more changes, this will serve nicely.
