Hi Bob,
Peco N Gauge rail joiners work quite well on code 75 bullhead rail. However, many users of such rail don't use any joiners. The track panels are carefully glued down in alignment with each other. Etched dummy fishplates are then glued over the rail joints. Alternatively, the Exactoscale plastic locking fishplates can be used and look good, but are very fiddly to use.
regards,
Martin.