Red,
The standard fan of that vintage drew 15-18 amps. The front fans draw 4-5 amps each. We haven't had a problem using the 30 amp relay with all three fans. Even our optional fan that draws about 20 amps seems to be OK with the front fans.
The wiring changed some time after your car to have two plugs coming out of the main harness, but I changed the system back to a single plug a couple of years ago. Now I include the "jumper" in the front fan harness. 'Makes the system cleaner when the front fans aren't installed (and saves me work, too
).