I will inform following matter which could be a problem time to time with 5 hp compressor.
Recommendation is to use about 5 hp compressor with mortar sprayer but this compressor need usually
3 phase power and this is not a available everywhere.
My solution is to use two 3 hp compressor and split a hose from both compressor to one hose and
you don't have any problem with air pressure.
Perhaps someone is noticed this earlier but it is good solution.