Nobody suggested adding weight at the collar. They suggested adding weight inside the shaft at the base. The truth of the matter is that you likely don't possess the knowledge to figure out if this was done on your special shafts without cutting them in half.
All the cuemakers who responded to your 1237 requests all told you that wood heavy enough would be difficult to find. Every one of them is capable of making the shaft you wanted, but didn't know of a source for wood that heavy. Which brings me to my next question...how do you even know how the wood was 'torrefied'? Maybe it was just roasted...which is not torrefication.