I understand you whish to go with parallel, and you can with good MC4 Y type conecters, but I tell you why it's much better even if you have shading to go with higher voltage.
Shading wont stop your system making power as most if not all modern panels have bypass diodes which will let the rest of the panel (S) work fine, and as the system has higher voltage it will wake up the MTTP charge controller earlier in the morning which will produce power earlier, and carry on working later on in the day, and it will keep on working when the panels have shading or badly overcast raining, but for me its the efficiency losses you will get by going with higher amprage instead of higher voltage, which means you will need to spend more money on much larger cables from the panels Y connecters to the charge controllers, but you will still have more efficiency losses.
Good luck, Aaron.