I used merge blocks so that the two items would be treated as one grid. The problem with connectors and rotors is that they are still considered two independent grids. The problem problem with that is that when in flight, the item that is being carried will drag down the ship despite being strong enough to lift it. Merge blocks solve this by making them one grid. The merge is not permanent, however, as all you need to do is turn off the merge block and the grids will unmerge, assuming that they do not connect elsewhere.

Hey - idea:
Use rotor heads/advanced rotor heads rather than merge blocks/connectors. Easier connect/disconnect (just drive up and press attach), and no power required on the module side.

I've kinda started working on some of my own again. I'm currently fine tuning a series of power cores that can work both in large ships and colonies.

Well you will find plenty of them here.

I like modular systems.