Ideally you want the switch on the coil side rather than sending the heater current through it. That would mean running the wire all the way up & back from switch to the battery end and all the way back up again for the power.
But if switch is designed to take that current, have at it I guess.
My preference would be as shown. Convention is to switch the relay coil, not the load line.
Sure, as above, any source for the relay power is fine.
Green wire on either the fall detect switch or the ignition relay is good.
Originally Posted by Marks Daytona
... I was wondering if the numbering differs for different relays ...
They are always the same - the other terminal that could be present is 87a - that is the Normally Closed contact
N/C is exactly that - 30 is connected through to 87a and when the relay is energized opens 87a and switches 30 to 87 instead.
You can buy relays that have built-in fuse holder for the 30 input and/or with the diode already installed.
Those are added features that make installation simpler - one stop shop so to speak.