A competent contractor would be first recommendation.
Or a competent consultant.
In fact, if they are not necessarily selling and/or installing the product then the Contractor would probably be acting as a Consultant.
House of worship, seats 425 two bose 802 III stacked in the center flown paired with some 18" subs on the floor.
What is the room shape and size? How high are the speakers flown? What are the room finishes? Where is the stage? What type of services and what is on stage?
While the vertical pattern of the 802 Series III is apparently as small as 30 degrees at around 3kHz, it also seems to be 80-85 degrees at 1kHz and 4kHz and 100 degrees nominal, so I am particularly curious as how a situation that lead someone to apply stacked 802s would relate to using the TOA HX-5 or a line array which are generally used where a narrower vertical pattern is desired?
The short throw of the 802's has been my main issue. If I run program levels at 92db I get multiple complaints. I try to stay around the 88-90 area at max. I also have some dead spots on the edges with the 802's that it appears I could overcome. If I set each speaker to be at 45 degrees I will have a full 180 degrees of coverage opposed to the 120 degree the 802's give me.
Be careful of assumptions made based on a single nominal coverage pattern. For example, the HX-5 is a nominal 100 degree horizontal pattern but the actual pattern apparently varies from 360 degrees at the low end of its response to around 50 degrees at a bit above 6kHz.
In comparison, the Bose 802 Series III is a nominal 120 degree horizontal coverage but seems to vary from close to 200 degrees to as small as 20 degrees at around 6kHz. The design of the 802 also results in some potentially significant lobing from about 2kHz to 10kHz, the 4kHz pattern noted above is a result of that as at 4kHz the horizontal response appears to be 6dB down at 10 degrees off axis and almost 12dB down at 20 degrees off axis but rises back to only a couple of dB down around 40 degrees off axis. And at 2kHz the response 20-30 degrees off axis is 4 or 5 dB greater than it is on axis.
The point of all this is really that a single number nominal coverage does not necessarily tell the whole story and much more so with some speakers than with others. This relates to both the coverage of a single speaker and how multiple speakers may array together.
Aso note that depending on the speaker locations, seating configuration, room finishes, etc. you may have to balance coverage with the energy hitting the walls and ceiling. While the goal would likely be good coverage of the seating and minimal energy hitting the room surfaces, in many situations a compromise may be required.
On the HX-5, it's easy to think it is something it isn't. An entire 'array' is four elements that are a total of about 21-1/2" high so it may be easier to think of it in terms of a compact box with a variable 15 degree, 30 degree, 45 degree or 60 degree vertical pattern rather than it being a line array. Compared to the Bose 802 Series III it is probably not going to provide a significant increase in response or output, possibly a bit less low end and bit more output which depending the rest of the system and your use may essentially offset one another. But the HX-5 may provide a more consistent and controlled pattern, especially more controlled in the vertical axis.