Is the heating coil the only large Load you can put on the DC system?
Pre meanwell days, When I had to trick my schumacher into seeking 14+ volts at max output when solar already had battery voltage over 12.8v, I would load my battery with my headlamps, fog lights, blowermotor on high ect until voltage would drop to mid 12's, then restart charger, then remove loads.
That was about 45 amps of load.
Granted all I had to do was turn a switch to put all these vehicle loads on the house battery.
Now, I don't even have a house battery, though I could drop one in place pretty easily if my capacity requirements decide to increase.
Not sure you can test the full output of an 80 amp PD unless you have that much in loads or batteries that can accept that much, but you should be able to test if it works and the wizard/pendant can control the voltages sought at the push/hold of a button.
Finding adequate loads for depleting a battery/ or loading a power supply/charger should not be difficult, since most times we are trying to find ways to decrease these loads.
The inverter is a great battery depletion tool. 1500 watts HF inverter, run an angle grinder or a drill should be good for 50 amps. A series of 115vac Box fans on high. Finding large loads should not be an issue. Hooking up the heating coil sounds like way more work than using the inverter at 800+ watts.