More solar

My dilemma.

I have 5 solar panels, 2 new 40w and three old Solarex 40w panels. They are all 12v panels – approx 19-20v open circuit. Are they compatible to hook up together. I intend to use a Morningstar 15 amp Sunsaver MPPT regulator. Ed C got my juices going the other day when he described his set up - two sets of panels each hooked up in parallel and then connected together in series then to the regulator or controller. Would the “parallel then series” set up improve the compatibility of the two sets of panels given that the voltage would be the sum of both sets. The controller apparently can handle the voltage.

Next question. My vehicle Disco 2 has a calcium battery and I think a 140 amp alternator. For vehicle charging of the leisure battery when underlay will the Disco set up harm an GM if it whacks it with some heavy amps. Isolator and cables are more than adequate (Redarc and 2 B&S).