Need some help on air pressure through a manifold and optimal leak/pressure rate

I have a small pump system for an aquarium, and have decided to build a small manifold. The total volume of the manifold and the tubing is 2.9828 cu inches. Here is my pump specs:

Inflation time < 8s (from 0-200 mmHg in a 100cc tank)
Air flow > 70mL/min
Max pressure > 360mmHg
Leakage max 36mmHg/15sec from 300mmHg at 70cc tank
Pump time - 7sec on / 7sec off

From the pump is a 3/16" x 12" tube (volume = .3311 cubic inches) which attaches to a small cylindrical manifold (1"x3" - volume = 2.3571 cubic inches) that has two air rails (each air rail (1/4" x 3" -volume = .2946 cubic inches). Total volume should be 2.9828 cubic inches.

I was hoping to see if someone could figure out how big of an orifice I would need on each rail for maximum pressure, within the 7 seconds on, 7 seconds off (basically optimal orifice pressure and size where manifold drops stays at a constant positive pressure at the end of the 7 second off phase wherein the 7 seconds on phase starts to pump and build pressure. Any help on this would be appreciated. Thanks.

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