To a degree you have it backwards. In general it is better to put more money into panels with greater output and let the excess be clipped during peak sun hours as you have more reserve capacity when the sun is not bright or is lower in the sky or there is partial shading.
MPPT provide less clipping (when panel output voltage exceeds the charging voltage to the batteries of 14.5 volts. In this scenario the MPPT controller works much better than a PWM charge controller.
Most people do not have a clue as to their specific demand profile. How many start with a Trimetric or other accurate digital charge monitoring device? If you need 100 Watt hours during the night and are going to replace that discharge the next day during 8 hours of daylight and have two 6 amp output panels that is going to be enough to bring the battery bank back to 100%.
If instead of 12 amps per hour you add 18 amps of charging capability you gain nothing. So what if the bank is recharged in 5 hours instead of 8. What is gained? Absolutely nothing.
Currently with commercial power production this same approach is being taken. If an inverter is rated at 105% of its nominal input then the solar arrays are built that provide this 105% to the inverter. Over the course of the year the total output is higher with the same cost for the inverter, racking, wiring, etc.