I see what you mean Steve.
In that case I suggest the way forward is to reduce the thickness of the pick, and maybe the adze. Then because the pick will be too weak sideways add a long curved tail onto the adze head, welded along the top of the pick to make a T section. The T can be stopped where your stress analysis shows it is not needed, but certainly make it long enough for all of the users hand, to make the axe more comfortable to hold. The tail can have a widening, if needed, to make a partial end cap to the ferrule. The pick section would now be in 2 parts a pick and a separate adze support web.
Advantages:
it makes the titanium pick more equal in thickness to the ferrule wall to aid welding,
it might be lighter,
it should be more comfortable to hold,
even less materials cost. (I bet you would get the separate adze support web out of the biggest lightening hole in the pick. The "adze tail" could be a separate component from the adze head.)
Minor points:
I was looking at the "adze support web" on my axe and there seems to be a fraction too much metal at the ends of the web. The web sticks up above the weld, and I catch my glove on it occasionally. I will file mine off but if you increased the radius of that part by say 2mm, (to make the metal component smaller) you would loose weight. You may have to change the hole position or size. If the hole is important increase the radius Ymm and move the centre of radius away by Ymm,
I imagine the ferrule need not be a square ended cylinder, the top end could be a bit cut away, and the CF too if neccessary, say X degrees at the sides,starting from near the edges of the T section, to make it somewhat more comfortable to hold.
Making the adze head shorter, to save weight to allow a bit more "adze sharpening meat" seems a good thing.