Abstract: Exemplary substrate processing systems may include a chamber body defining a transfer region. The systems may include a lid plate seated on the chamber body. The lid plate may define a first plurality of apertures and a second plurality of apertures. The systems may include a plurality of lid stacks equal to a number of the first plurality of apertures. Each lid stack may include a choke plate seated on the lid plate along a first surface of the choke plate. The choke plate may define a first aperture axially aligned with an associated aperture of the first plurality of apertures. The choke plate may define a second aperture axially aligned with an associated aperture of the second plurality of apertures. The choke plate may define protrusions extending from each of a top and bottom surface of the choke plate that are arranged substantially symmetrically about the first aperture.