Plotting Double Munar Orbital Rendezvous

[sevenperforce]

I want to do an Apollo-style mission, with one difference: the Lunar Module launches first, unmanned, and enters Munar orbit. Then, the Command Module launches and docks with the Lunar Module in Munar orbit. The astronauts transfer to the Lunar Module and proceed as in Apollo, with the LM being used for descent and ascent and then being discarded. 

My question is this: where should the two spacecraft rendezvous for greatest overall efficiency? Should they aim for a high orbit or a low one? A low orbit takes advantage of the Oberth effect, but a higher orbit means it will be easier for the Command Module to return.

If such a mission was carried out in real life, would it be better to use a place like L1 or L2 for the rendezvous?

[Reactordrone]

The lander has the highest delta-v requirement so I'd optimise for lander efficiency and rendezvous in low orbit. A high orbit will only save a few tens of m/s at most on the return to Kerbin.

[Wcmille]

Some thoughts:

The command module can also have an awful TWR, but the lander TWR must be good enough to land. Awful TWR can mean better dV, letting it do more work.

The lowest energy circular arrival/departure orbit is its gate orbit. There should be no reason to arrive at a higher altitude. Arriving lower may be advantageous, because the command module is doing the work. https://en.wikipedia.org/wiki/Gate_orbit

I find the higher in orbit something is, the easier it is to rendezvous with it, because it's accelerating less, and there's more play in designing rendezvous orbits. It may also be advantageous from a playability perspective to place the orbit where you can time warp adequately.