I am using a Ron Francis Express Panel in the rear seat delete area and have the following setup with a Ford type solenoid in the trunk to keep from having the starter cable energized at all times. I laid out a very basic diagram up to the point that feeds the new fuse panel so that the basic setup is known, which should provide enough info to answer this question.
Rear seat delete fuse panel location. Driver side.
under dash relay station
The one thing I am not sure of is how to best way to get Switched power bus bars at the front and rear since I'm using the master power cutoff and high amp alternator shutoff solenoids. I already have "always on" bus bars at the rear seat area, under the dash and at the radiator support. Ideally, I'd like to place "switched power" bus bar at the rear seat and dash area to run my feeds for switched items. I don't think I need one for up front because the headlights and horn are "always on" circuits. If I can't run something from the existing solenoids in the trunk, I guess I'll have to have a heavy duty relay(s) capable of approx 200 Amps total. I'm using the Ron Francis headlight feeds from the fuse box to be the the trigger wires for the headlight relays since the panel is in the rear and I'd like a heavy gauge feed source close to the headlights.
I also built a separate relay station under the dash for things such as the water pump, 4 Window relays, the AC compressor, AC fan and the MSD box. I'd like for most of those to get their feeds from the under dash.