In general I tend to rise the local system chance, and lower the number that a system is recognized as a local system.
I suspect that is why I usually get a lot of loops. However I came to realize that if you lower the range of local systems, eventually you run out of system that can form a loop as there are no more system that are considered local, and system has to be local to form a loop right? or so at least I think it is working. (IE if local range is 8 and you are in system 10 and system 2-18 is already known, there are no more local system to system 10 and a loop would be impossible, right?)
I miss the old VB mechanics though, where you cold see the system number in the galaxy window.