I mean...there's a subforum that's concerned specifically with toys and stuff -
viewforum.php?f=12
But ultimately it's up to whoever creates the script to make decisions about stroke length and location. If you have a strong idea of what feels good, you should try making some scripts and showing the world how it's done ;)
Check out eroscripts if you haven't already, there are quite a few cock hero scripts out there and you might find something you like:
https://discuss.eroscripts.com/