Alex, I used to use an NCE 10 amp system, and I use US gauge 10 wire as the main feeds in a "star" or "home run" configuration, i.e. every wire goes back to the power supply.
I do have some trains that do indeed draw 10 amps. My feeders are 30 to 40 feet apart, I use SS rail and SS Split Jaw clamps. This arrangement has been a good balance for me between number of feeders and gauge of wire.
Here in the US 10 gauge wire can be had in various configurations, but I buried conduit along the right of way, so I was able to use inexpensive household wiring, with a thin insulating jacket, as opposed to wire that was designed to be buried in the earth.
Even though SS is less conductive, and I use sectional track so I have a lot of joints in the rail, this has worked very well for about 10 years, and very few issues on bad joints. So, basically zero maintenance in 10 years, and for me this is success.
Regards, Greg