heh, I was just (half) joking about the forge.... just want to be first in line for the Tsourkan integral bolster
Seriously though, i cant imagine the few grams of extra weight just in front of the handle would have a noticeable difference. Even comfort-wise the area that you'd ever actually be pushing on is far enough fwd that it's down to the same thickness of the stock that you're using.
Now if you're taking about making that even thicker and extending the thick section out to further over the heel... well that might be interesting...
Where is the current "sweet spot" on your alpha test blade? One of the things that I thought was really "off" with many of the heavy gyuto's I've used was that the profile was not well-matched to where the blade naturally wanted to contact the board first due to it's blade-fwd balance.
Properly tuning the profile to the balance or vica-versa is, IMO, one of the areas for greatest improvement in the "heavy gyuto" world. You could gird it close and then fine-tune it using the handle weight / adjusting the thickness of an end-cap.