Generally with home PV all the panels are connected in series strings.
In Series circuits the length of cables between connections does not have to be equal.[
G.D maybe]
The thing I see a lot of DIY get wrong is to
[NOT] keep the Positive and negative wires close to each other.
Installed incorrectly you will have this nice big loop of your roof.
In making sure that I always have Positive and Negative running close to each other my negative wires is much longer than the positive wire.