Domes on Horns vs Compression Drivers on Horns

I understand. I would like to use a rectangular conical wood horn calculated with Synergy Calc. I think this shape is particularly convenient for integrating the midwoofer. To get the dome tweeter as close as possible to the midwoofer I'm going to partially cut the sides of the NE19VTS 3d adapter. In this way, between the tweeter plate and the first useful point of the woofer I should have about 9mm.
The non-round shape of the Peerless SLS 85 woofers I think will be very useful in this situation.
II also believe that I will be able to recover a few millimeters, perhaps even giving a shape of sausage or a smile to the port holes of the midwoofer.