I'm a little late to this party but will offer my 2 cents.
My general rule of thumb, without writing a huge, complicated reply, is have the primary fan come on 20 degrees warmer than the t-stat. Set the secondary 8 degrees warmer than that, so 28 degrees above the stat temp.
I don't want to start any kind of war, but I personally think 160 is too cold of a stat on the LT1 for street use (track use, different story). Low temps are not good for moisture removal, oil temps, or combustion efficiency. I recommend a 180 degree stat. Then set primary fan for 195-200 in this case. If you insist on running a 160, then set fans for 180-185 if you really want the engine to run that cold (contrary to rumor, that temp isn't ideal for street use). I wouldn't go lower or else the fans will run too much and burn up the harness.
When you do your own custom program, ideally you would run 2 wires from the relays back to your dash and wire up LEDs so you can monitor the fans. If you connect those wires to the ground side of the fan relays, you can even "override" the PCM, forcing the fan on, using switches on the dash wired to ground. So a single wire (per relay) could serve as both indicators and overrides. I have this setup on my B-Bodies. It took me a few tries and tweaking the numbers before I was happy with how much the fans were running versus how hot the engine gets.
Note that any fan temp adjustment, even just a few degrees lower, will be better than stock. No need to go crazy.