With some practice you should be able to get satisfactory results using Tri-X with long exposures. I've done so several times photographing under moonlight with exposures ranging from 10 seconds to one hour.
While I've read articles about the reciprocity characteristics of various films (including the excellent article by Mr. Bond referred to earlier), I don't work with films in any technical manner for night photography. I'm familiar enough with Tri-X to be able to estimate a baseline exposure under most conditions and I'll usually bracket around that baseline.
One trick that I find helps me is to use a development technique that helps control contrast. I develop in either Diafine or use stand development in very dilute Rodinal. Either method essentially eliminates time as a factor in development. Diafine (a two-part developer) is used for 3-5 minutes; the time is not critical. With Rodinal and stand development I typically use a 1:200 solution for two hours but, again, the time factor is not critical.