I'd think you'd have to look at how much is going to be pulling power at one time. A battery tender pull no power, ever. An alarm is only pulling when it's armed, when all other things should be off. Radar detector/GPS/etc is what you need to figure out, should be in the paperwork or power cables. I think you'd be surprised at how little some things actually pull.
One suggestion, instead of having so many wires coming off your battery, run another fuse block in your trunk. This will help keep things from getting bunched up on the battery terminals and also add fused protection to each thing you hook up. the only thing that should be straight to the battery would be the fuse block and battery tender.