Polaris does not always stay "True North?" The only reason it was "True North" is because someone of the searchers around the Civil War Time laid it out that way. Why would anyone bury a treasure and leave a 10 or 12 foot pointer on the shoreline to exactly where the treasure was buried? Stupid Pirates, I guess. But Pirates did not have the know how to make large works of tunnels or shafts.
The Earth's Axis shifts from 22.1 degrees to 24.5 degrees over a period of about 40,000 years. The Earth rides up and down the scale every 12,900 odd years through two cycles of up and down, with all of these changes over years nothing stays "True North"
It is essentially in the same position it was now as when it was surveyed by Roper. The precession cycle takes roughly 26000 years. 80years/26000 x 360 degrees= roughly 1 degree since 1940. There is no other star to align with for N other than Polaris. It will continue to be the best beacon for a while. There absolutely is a True North. It's the position that never changes in the night sky when you look to it as the stars rotate around it. At that point is Polaris in these times. It's position remains the same at all times as seen by us. The next polar star will be located in Cygnus in another 3000 years. This was deduced in Europe in the early 1600s, and probably earlier but unappreciated then. In Egyptian times it was Thuben, not Polaris. Things are aligned with Polaris now, and that helps us to know it is put down in recent times as opposed to say in Greek or Roman times. There have not always been great polar stars. In Greek times they had their preferences. To navigate the Mediterranean they used what was later called the Mytre of St Peter and/or Triangulum, a perfectly straight (90 degree) triangular asterism that was directly above their heads South of the tip of Greece NW of Alexandria. In fact if you projected a straight line from this point where Triangulum is in zenith through the Pillars of Hercules it would intersect North America at Mahone Bay, NS (Haliburton's Chester Bay). This is something that had been realized by Francis Bacon since he uses that description of this alignment in his works. His knowledge of that little fact we can show.
It is with this knowledge of the OI location that Haliburton likely worked upon. He would have been intrigued as a Nova Scotian. I suspect the knowledge of this came to him through his relatives with which he spent significant time in the period immediately prior to writing "The Old Judge" vol. I. The same relatives later founded the Francis Bacon Society in England. Haliburton was likely all over the speculative Bacon ideas. That's how Bacon gets written into OI if you ask me. He understood that Bacon saw significance in this area in at least a few celestial ways. It is doubly significant because by the current position of Cygnus is in Zenith over the same area. This is the level of coincidence that Bacon loved to emphasize. Cygnus, of course, is the Swan that everyone wants to trace back to Shakespeare. The crazier notion that Bacon was Shakespeare was actually championed by Haliburton's niece Constance Mary Fearon Pott. About the same time she started publishing books about it the OI ground story shifted to the money pit being a chamber of manuscripts. People on the ground in NS have obviously been guided by the Burtons' ideas for a while. I suspect they were from day one in 1848 when these searcher shenanigans started.
The magnetic deviation you suggest isn't what you claim it is either. It varies wildly non linearly over time. To know exactly what it was at the time the island was first surveyed you can stumble over to the NS Department of Natural Resources site for a peek at the grant map where you can actually figure out exactly what the declination was at that time. It was not 30 degrees NE. Not even close. You are just spouting horrible information that will potentially impress those who cannot verify it.
There is no material "treasure" in Chester Bay. The correct question is what is the significance of OI in relation to the story it is part of, a story closely related to Haliburton's account. It's today more real than it ever was indented to be. It was most likely made that by individuals who sought to put down on the ground ideas they took inspiration from on paper out of admiration for one man's ideas about this place.
If you are looking to expand on the Cathar suggestions in Haliburton you will need to study up on Manichaeaism. Enoch's vault as a target is quite instructive, because in that mythology you can never reach the inner chamber exactly as you will never find the vault in the money pit today. The Enoch legend tells you that the walls will crumble and that the pit will fill with water right as you are about to reach it. Again, that's another detail of this modern story that mimics the old religious myths. The inner chamber is the knowledge of who you really are in the Enoch legend. That's part of the freemasonry take on your self awareness quest too.
OI is part of a great mythical allegory that was expanded upon by Haliburton and probably was staged by some Freemasons who see in him a father figure. It's certainly the case with Rosicrucians, a fraternal group that has many ties to the writing of the History of the OI mystery. The "Bible" of OI history was written by a NS Rosicrucian, Reginald Harris, as you know.
OI is like the Holy Grail or the Ark of the covenant in many ways. Don't be looking for those there, though. Halibuton was very shrewd when he predicted that men would die in shafts looking at the wrong spot for the wrong thing In Chester Bay. He does point you to your quest, though. You need to know who you really are. That was Francis Bacon's quest too.