Hi Tom,
FWIW, I apply a "light" mask to the image and only cite the "star" mask in the Local Support section of Deringing section in Deconvolution. I will also input a value into the Global Dark under the Deringing. This value varies (at times) depending on the image and its condition. However, generally speaking, the value of 0.005 works well for me.
And you'll need to do a Dynamic PSF process on the image and make sure that it is cited in the External PSF section of Deconvolution.
Hope this helps,
Mark