Hello Richard, Yoiu are right on all points, but the Alfasud kit had 90 degrees stacks, to face forward.
Mine will not fit 44 IDF (alfasud) - Dimensions of my curved horns: 44.8mm OD
They were beautifully made, two half welded together, the seams can be felt on the inside,
and on the outside, the blending is gorgeous, as are the 'bird and rock catcher screens'
Beautiful Italian artisan work.
On 45's, as I do not have 40's handy