If there are no walls blocking the view from left to right, try just one receiver in the center and just point the throttles in that general direction. You can add additional receivers if you need them later. I haven't use the PM42 so shouldn't bad mouth it, my recollections from a couple years ago tell me it requires programming and is a bit finicky. I like Tonys power shields. However, I will say that I still run my entire layout (19 x25 double decked) as one power district. I've never had a short it took more than a couple minutes to find. Usually a tool left across some siding! Yes, if someone forgets to throw a turnout or derails, the entire layout stops. That is why I bought the power shields, just been too lazy to install them!
For the reason of readback of cvs, I like either the Zephyr or the Chief. I bought the Chief 5 or 6 years ago, no regrets.
Throttle wise, I've liked the size of the DT300 and 100, but with the sound decoders now using so many functions, the 400 is a great choice, I'll have to get used to its larger size. Installed my first Tsunami recently, need funtion11 (I think!) to get brake squeal.
Hope my rambling is somewhat helpful.