Alex, I always used FITS Image Grader, it is free from the SGP folks, and is a stand alone app.. It can work through a whole file of subs,. FITS Image Grader will calculate "whole-image" Half Flux Radius (HFR) in order to determine an image's relative focus (lower values are better), Number of Stars found and finally a proprietary "Score" that takes both HFR and Number of Stars into account to provide a single metric (higher is better).
You can read the whole description of what It does, here:
https://www.sequencegeneratorpro.com...-image-grader/
It will break your subs down by filter sub- group and provides a nice report. You can manipulate the files, Mark them, etc.
Great tool in my opinion.
It is a good first pass at checking, and can eliminate having to look at a number of bad subs manually. I do still examine subs manually but usually just a scattered sample, after the Image Grader did it's work. My attitude was that if Image Grader was showing a score that indicated good focus and maximum stars then the sub was pretty good already. Incidentally, the SD figure is the standard deviation of the HFR, which is a good way of knowing how far out any particular sub may be from the Mean of the file group.