An SCC could draw maximum current from an overpaneled PV array and hurt itself. Or it could monitor current and never exceed what it can handle, even if Isc exceeds that.
Heat is created in SCC from IR drop through components like inductor, diode, transistor. MOSFET have very low on resistance, so most of their power dissipation comes while transitioning between on and off. The voltage during steady-state operation would swing between Vmp and zero, with Imp (or whatever lower current it is limited to by SCC wattage rating), dissipating energy J = 1/2 x V x I x falltime (during each transition.) Higher frequency switching dissipates more power, but allows smaller inductor (lighter, less expensive) less ripple in output.
We often compare energy loss in PV wiring (less for higher voltage strings) with loss due to efficiency of SCC (higher for high voltage strings). Also, high voltage strings saves money on copper wire. However, copper doesn't wear out (unless so hot the insulation gets damaged.) Shifting inefficiency to SCC in order to save money stresses SCC more. Over-paneling exacerbates that.
When overpaneling, could be worth aiming for a more efficient operating voltage of SCC so it generates less heat. At least, if you're in a hot climate.
If you overpanel by aiming half your array SE and half SW with a 90 degree angle between them, area presented toward sun is 0.7 times as much. That means you can over panel to 1.4x without exceeding electrical specs of SCC (most of the time; there is more area to capture extra light reflected off nearby clouds under certain conditions.)
With 90 degree angle, 5kW would be fully paneled for 3500W input. With an acute 60 degree angle, 7kW would be full paneled.
At 90 degrees each subarray has 45 degree angle to horizontal, isn't losing much from sun below horizon (but objects causing shading get in the way.)
At 60 degrees, more of panel's daily out put is lost to sun not above horizon.