was there a fuse ?
sounds like you fried the zener . ( not the first , American anyway, to do this )
lived under and infront of the gas tank ( under the ignition key )
... between the frame down tubes and front forks
iside the finned aluminum piece )
the zener will flow , when hooked up backwards , as almost a dead short .
( like a normal diode ) (with only about 0.6 volt drop ) ... this would have melted the insulation
on the wires to the zener ( the good news is this wire will not be used when upgrading to a
new style voltage regulator ) ... but check the harness , this is part of determining what failed .
( it fits with smoke and smell at headlight area ... the wire to the zener woulda been white
you may have fried the rectifier too
5his piece will also be replaced with a R/R ... but check that
that any wire insulation attached here are not melted .
( no smoke or smell from under the seat is a good sign ... but check )
to fix ;
20 bucks will get you a good , but generic Chinese regulator/ rectifier
60 bucks will get you a 'branded' regulator/rectifier with a warranty and customer service
60 bucks will get a new zener .. if you can find one .
as part of one step back and 2 steps forward
it would make sense to check the AC output from the stator
before buying any new regulator rectifier