Remote Starter Solonoid, someone check my homework please.

[Zonaman]

I'm wiring up a remote starter solonoid using a firewall mounted unit from an '87 Crown Vic.

Have I got this right? See below

1. Remove the cable from the positive battery terminal on the starter mounted solonoid and move it to one of the battery posts on new one on the firewall.
2. Connect another battery cable from the other battery post on the firewall solonoid to the battery post on the starter mounted solonoid.
3. Remove the ignition switch wire from the "S" terminal on the starter mounted solonoid and re-route it to the "S" terminal on the fire wall mounted solonoid.

Also, does it matter which battery post on the fire wall mounted solonid I use for which battery cable? Will mounting the solonoid to the firewall be sufficinet to ground it?