I use the recommended set up in the manual for live recording of 16 tracks on a combination of a Fostex vf160ex and a Berringer ADA 8000 (ultragain pro 8 digital). I take a line out off the "1st click" insert on my Mackie 1604 VLZ but you could get it from whatever direct out you have from your board. The first 8 channels I put directly into the Fostex line ins and the rest of the 8 tracks go to the "line ins" on the ADA. Then an adat line from the ADA to the Adat in on the Fostex will give you the second set of 8 live channels. Be sure to set your track recording format to "adat". Go to your main mixer and adjust all your levels and then adjust the gain levels on the Fostex and use the gain levels on the ADA for the other 8. Be careful that the sound guy mixing out there does not crank the live house board to much or you can get serious clipping unless you have the limiters/compression effects. Hope that helps.
Ken Wulff