Crossover instead of Kube on KEF?

If its not too much a task, perhaps it's just best to make a whole new x-over for the head unit with a new tweeter, taking some components from the high pass part of the bass unit x-over. I have Scanspeak 97000s which have the same mounting holes as the T33 when you remove its metal plate, but require a slightly larger hole for the Scanspeak's tiny horn bit. So a small mod and it will fit directly on the Kef plate.

As an aside, I was recommended ages ago to isolate the head unit more - by someone who praised to results of doing this with Kef 105s - and I coincidently have some granite slabs that fit exactly in place of the fabric'd top of the bass units. I was looking to remove the post the head mounts on and instead create an adjustable stand for it to sit on the granite via sorbothane .
Hey, how did you go with a granite slab for your head units?
I was just told that because mine have ribbon tweeters, I will have to keep them at 90 degrees to the slab/floor. I dont know how to achieve that plus it would need to be sturdy and vibration free. ( with the ability to move left and right. )
 
Sadly, I've not even finished refoaming the bass drivers yet! I've so many projects... need to prioritise, perhaps these so I can sell on my current speakers...
Anyway - as for your issue, perhaps you can simply angle the ribbons down by inserting something between the housing and the tweeter mounting?
You'd need to make sure the cabinet was still seeled, but some kind of adapter might work.