Electricity always takes the path of least resistance, so I would put separate feeds in, this will allow for future times when one circuit tires a little more than the other.
Mike.
I use these in EM, very useful for the sausage fingered amongst us!
https://westhillwagonworks.com/layout-accessories/634-rail-joiner-mate-n-gauge-handy-track-laying-accessory-pack-of-2.html
Mike.
I've been sitting on this for a while, so pin pulled and here it goes;
A train set is OO, a model railway begins when a modeller sees the light and moves on to EM, P4 or whatever.
Mike.
In the corner with my tin hat on.