<VV> voltage drop, relays question

[Jeff Schramm]

Are relays an option? The Tech Guide describes a procedure for
installing a relay to control the high-output fan, but doesn't appear
to have a similar procedure for headlights. I've been curious about
this since I saw an aftermarket headlight harness for Volvos:

https://www.ipdusa.com/ProductsCat.aspx?CategoryID=205&NodeID=1048&RootID=629

I'd like to know if it's feasible/practical to consider installing a
relay setup like this in my Corvair, or if it's just a waste of time.