Details on my Ferrari 308 USA to 308 QV Euro bumper and grill conversion

Here's the bumper comparison - original USA bumper on top and 308 QV euro bumper below

QV bumper is same width as USA bumper but
- QV bracket mount holes are 9 cm
- USA bracket mount bolts are 7 cm
- bracket mount holes are 10 cm
Using tubes and brackets the outside bolt holes line up with the QV bumper.
Note that the bracket mount holes are also basically the size of the bolts - not much slop in the event that the tube is rotated to raise or lower the bumper mounting location.
I believe that rotating the tube will change the space between the brackets so taking advantage of that feature might require elongating the mounting holes.
Inside mounting hole also has to be moved outboard by 1cm

... and a better closeup of the mounting points
mount

... and the bracket on the bumber (clearly no room to raise or lower the bumper by adjusting where the bracket mounts on the bumper)
bumper

Here' the tube mounting

I measure the distance from the vertical plate to the rear of the large tube mounting bracket to be 210 mm (large tube is maybe 10mm too short ???

The tube mounts into the front of the bumper area secured at the rear by a bolt through the hole and at the front by a U clamp something like this
mount

The tube has a plate welded to the front of it to offset the smaller bumper mount tube to the right location to align with the bumper mount holes.

The problem appears to be the plate that the U clamp is attached to - it interferes with the offset plate between the larger tube and the smaller tube.

The causes a couple problems:
... the tube doesn't go all the way into the rear mounting so I can't properly secure it.
end

The mounting bracket hole is approx. 15mm in diameter and offset by approx. 12 mm from the rear of the bracket. (Maybe this is important in trying to figure out how large the hole should be in the big tube ?)
By my rough measurements, if the big tube were able to fully seat against the back of the bracket the center of the holes would approximately line up
center of tube hole = 20/2 + 5.8
center of mount hole = 15/2 + 12

... the tube is inserted as far as it can go as it hits the vertical plate that the U bracket is bolted to
left

.. this also causes the bumper to sit out further than I think it should - even with the small tube inserted as far as it will go into the rear small tube (although I don't know the proper bumper spacing)
bumper

Bumper height adjustment feature

I'm not sure the the default height of the bumper is right. It looks like there is too much space between the bumper and the front ot the car height

I can see one way this could be adjusted.
.. the large tube mounting hole is larger than necessary. The large tube could be rotated to raise or lower the offset front small tube onto which the bumper bracket is mounted.
annotated

.. I could see how this would work but I'm guessing that the bumper bracket holes would have to be elongated as the rotation will put the bracket mounting holes at the wrong location to match with the bumper itself.

Summary of problems

- the big tube rear mounting hole to front plate mounting distance is too short (plate hits front of vertical member and restricts the back of the tube from properly sitting into its mount -this ultimately also puts the bumper too far out even with the smaller tube fully inserted into the big tube offset smaller tube.

- the bumper bracket spacing is different from the bumper itself. The outer holes line up so only the inner ones need to be re-drilled. It is possible that these holes have to be elongated to allow the up down rotation to take place without messing up the left to right mounting offsets.

Possible Solutions

Some ideas

replace rear tube with a longer one (It will seat properly allowing it to be bolted in and if I understand it right using a larger hole in this location will allow a rotation to allow for a bumper height adjustment)

cut a small amount off the bracket small tube (one that mounts to bumper) so that the bumper can be recessed further. The bumper depth is set by the insertion depth of the bracket small tube into the plate mounted offset small tube attached to the large tube.
redrill the inboard bumper bracket mounting hole to match the bumper (9cm offset instead of 10cm)
possibly elongate the bumper bracket mounting holes to allow for bumper height adjustment (once the other stuff is done need to see if this is really necessary.

I suppose another possible solution is to cut away a portion of the vertical plate at the front of the car to allow the existing tube to fully seat.
I guess a further solution could be to drill new mounting holes in the car where the tube sits at the rear.

Cutting the car is not my first choice. However this would also likely also solve the bumper out too far problem - if not the same solution could be applied by cutting some off the bumper bracket.