domelight wiring question

I have a hornet 554t on a 95 accord.  i read the section in the install manual about how to hookup a relay to add domelight supervision.  I bought an automotive relay but the only thing is that it has a pin for 30, 85, 86 and 87 but no 87a.  is that pin necessary?  i understand the install as:

find a constant 12v source and splice one end of a new wire to that source and the other end of the new wire to an inline fuse (30 amp?).  on the other side of the fuse run a wire to pin 86.  attach the BLACK/ white wire from the primary wiring harness of the 554t to pin 85.  then cut the original domelight wire, already in the car (which i understand to be BLACK/ WHITE/ silver in a gray connector to the right of the steering column), and attach one side to pin 87 and the other side to pin 30 (does it matter which way?).

am i close?

just in case:

technical data:

coil voltage: 12v

pull-in voltage: 6v

coil resistance: 66 ohms

nominal current: 160ma

drop-out voltage: 3.6v

spst contacts: 30a at 12vdc