I have seen the episode guide on the wikipedia. I do not see a listing for an episode that featured the Vulcans joining the crew of the Enterprise for the episode.
The only episode of TNG where any number of Vulcans came about the Enterprise for the episode was in Season 3 when Spock's dad, Ambassador Sarek came aboard for a mission. The episode is named for him "Sarek". Only one other Vulcan came with him though. Any other story with Vulcan's joining the crew wouldn't be on TNG
That there is an episode with Vulcans! Was there any episode where they described the deflector in any detail?
Table the starship construction issue for a bit. Anyone seen "V"? It stands for "visitors" but does it also stand for "Vulcans?" The enemies of the Visitors? Do both these species want to eat us? Are the visitors less amenable to eating us than the Vulcans?