Kirsch,
Now you’ve got my noggin’ working!
For regular optics I build my own targets with Excel and a printer. There I use four black squares with white space in the form of a cross between them. This allows me to use a target four four individual groups if I chose to.
I can do the same thing with aluminum foil except for having to cut out the squares and glue them into my desired spacing.
Thank you and best regards.
Three 44s
