I have an interesting plan for this.
The Sol-Ark has 3 MPPT inputs.
You have 42 panels total with 18 facing east, and 24 facing west.
Split up the east roof into 3 series strings of 6 panels each.
Split up the west roof into 4 series strings of 6 panels.
Now you have a total of 7 stings coming down to the Sol-Ark.
Put two of the west facing strings in parallel on one MPPT controller. 12 panels at 300 volts x 16.8 amps = 5,040 watts in ideal sun.
Put one west string in parallel with one east string on the second MPPT controller. Same 300 volts, but the peak current will be less as the east panels will fall off as the west panels climb as you cross solar noon. With the 2 strings having the same panel count, they will current add pretty well. Separate MPPT's might do a little better, but not by a lot.
The third MPPT controller then gets the last west string and 2 east strings all in parallel. This will requite a fuse on the separate strings as 3 x 8.4 amps will likely exceed the max safe fuse rating for the panel wires. You still get the same 300 volts, but the theoretical max current is up to 8.4 x 3 = 25.2 amps. This is still under the 26 amp MPPT input limit. If all 18 panels had full sun, yes, this could try to hit 7,560 watts, but since they are different angles, you again have the east panels falling as the west panels come up.
I have 3 rows of 5 series panels going parallel into one MPPT. They are at roughly the same angle, but I do get shadows from trees in the early morning and late evening, and when one row is shaded bad, the other row still makes full power. And with partial shading, the power available still adds.
If you find you are not getting the energy you expect, you can also just add one external MPPT to handle one of the 6 panel strings. That would then give you 36 panels on the Sol-Ark directly, 2 strings of 6 into each MPPT controller channel. With this setup, I would do 2 east rows on one MPPT, then 2 west rows on each of the other 2 MPPT inputs. The final east MPPT string goes to the external MPPT controller. To stay with the 6 series panels, it would still need a 400 volt rating though. Victrons or an Outback or Midnight MPPT will cost a bit but will do a great job. You would need to rewire the panels to 2S3P to get away with a 150 volt controller. My cheapo BougeRV charge controller would be a bit over it's input power limit of 2,400 watts, A 250 volt controller like a Victron would allow 3S2P and allow thinner wire for the array wiring.
