Thank you for the question... I have two theories on the size, both would fit into the supposed 30 x 30ft void found on Oak Island.
The capstone, as it relates to my theory is 2 royal cubits in length, about 1 meter high with a square base of 1.6 meters. In this example I used the biblical reference because of the vast similarities between the two belief systems. I believe a lot of the information in the Bible came from Sumerian texts, but character names have changed along with stories to relate to the modern times. The creator God Aten the giver of life, for example...
My second theory relies on basic fact of observation, not trying to be snarky but sometimes you just gotta stop, clear your mind, and perceive. You can walk freely on top of the Great Pyramid today, you'd be able to walk about 30' in each direction. So at the very maximum the capstone would have been just shy of 30', about the same size as the void they found on Oak Island.
Yes, early reports of drillers testimony explains how one team drilled through gold. It had enough concentrated gold shavings along the drill bit that he believed that solid gold was struck. This, however, was held a secret by the gentlemen and if I'm not mistaken, the hole had collapsed or he had passed away before it could be further excavated. There is much lore and fabled stories surrounding the Island, enough to make you think...
There are several reports of the capstone being made of solid gold or gold plated. Google will provide.
It's whether you chose to believe the source or not. My particular method accepts all stories as true and sources of those stories as credible. When you disregard someone because of their race, creed, color, gender, language or faith then you've lost, period.
So both assumptions can fit into this void, capstone was solid gold or gold plated, the size is either 2 royal cubits or about 30' squared.
Thanks again for your question, if you have any others please ask away. See if any of your friends have any questions either, I've found many of my own questions arise during these Q & A's