No. What makes you think I did?
I don't. You were making a point about the weapon's general unwieldiness, my guess. That such a gun would spread a tank like peanut butter is also certain. Making the hit would also likely not be that difficult, assuming it was in the monster's field of fire. Perhaps it's make a good base gun - but probably no better than the 5-inchers we already have (not sure what those are modelled after).
By the way, while I give you credit for making a valid point, the Wehrmacht did not share your view - since they shoehorned the very similar Pak44 128mm byotch into a JadgTiger (The Pak44/L55 - I believe the L designation being the barrel length in multiples of caliber) using a couple of shoehorns and some KY. While the Pak 44 was NOT the same gun as the Flak 40, they were both made by RheinMetall Borsig and both suffered from enormous curb weight - to the extent that a towed version of the PaK 44 was cancelled - and topped out, like it's AA counterpart, at over 10kip.
so, yes, mostly flak towers for 128s - except when they were in the hull of the heaviest AFV to see service in the entire conflict.