Its kind of cute
Not sure targets are random ... a few tries and i started laying in wait for them as each one follows a fixed path. Mind you ... i'm a lousy shot ;-)
A time contstraint is not hard to do either.
But my suggestion still holds ... whatever you feel most comfortable with .... and is sufficient for what you want to do.
Maybe if i get time i might build a shooter ... just never been big on them
Good luck with it though
griff