Tweeter placement in spawn horn

[bacon665]

Im working on a set of solid oak Half changs (still cutting wood so no assembly pictures yet).

I plan on using the Pioneer B20 which as many of you may know lacks its high range. To compensate a small tweeter is added. Typically this seems to be the 3/4inch glue in dome. As this is already a horn why not go with a horn tweeter. Anyways from what i see most people place the tweeter on the same baffle as the speaker. I had a slightly different idea today and i will attach an image of the placement just in case it isnt clear in my text.

The reference point for the description is the anterior baffle which contains the main driver. From the horn there is a distal Baffle whose origin is from the reference point. This baffle is also proximal the the posterior wall with a 3/4 inch gap. My question is what would be the effect of mounting a horn tweeter on this board firing into the cabinets horn. Since the tweeter and the box would be firing into the horn from the same angle the deflection of the sound should also be the same.

The tweeter in question is this one or possible these.

Now angle of incidence says that energy will be reflected at the original angle plus 180 degrees minus 2 times the original angle.
The baffle of the horn is 45 degrees.
The first tweeters dispersion range seems to be 37 degrees in all directions of the center axis. the second appears a little wider at about 60 degrees.

We will start with the 37 degree deflection. The forward deflection will not hit the baffle so the upper limit is 37 degrees from the anterior baffle. The backwards deflection will hit the baffle forming an 82 degree angle.
This means the forward deflection will be 127 degrees.
So the total dispersion of the horn in this position is 164 degrees.
If this sum was large then 180 that would mean that the feilds would overlap which could cause some distortion.
Although this form of distortion could also be present anyway. if the horn modulates the bass compressions coming from the mouth of the box then we are presenting with two marginal overlapping fields. still yet if the tweeter is overlapping itself we would produce two marginal fields that overlap once and then a very large field that contains three waves overlapped.

Any comments as to the pros and cons of this versus placing them on the reference baffle?