It is a reasonable idea to space the outlet evenly around the manifold.

At one time I used one much like yours, but put 400 lbs/A into a solid grass sod. For a good while I used the clear plastic hoses, designed for anhydrous, and at that rate the flow was in liquid form. Worked like a champ.

Just to be sure you have a good closing system as above 50ºF AA likes to boil out of the slot, unless sealed.

Just for the record, nitrogen fertilizer for a grass hay meadow, expecting 8 Tons, 12% CP hay can easily be in the $150/A range. Add some phosphate and potash and some real money can become involved.

BOOM!