Bursu

or  closely related to b above:
c) 3900W + 3900W (MPPT1) and 7800W (MPPT2)

I concur with @GreenFields
16s1p on MPPT1 will safely provide 11,616 Wp (11.69% above 10,400W) at 734.24 Voc, 611.68 Vmp, 19.00 Imp and 20.11 Isc
At 0 deg C, Voc will rise to 780.13 Vdc which is still below the 800 Vdc max DC voltage of the Deye 12K 3PH hybrid inverter.
 

Hello beautiful people. I have 13 panels installed on each of the two MPPT, in my garden over grass, at 30⁰. So 26 panels in total split into two equal strings.
The installer said is ok to have 13 panels per each string since I don't go over the maximum VOC. However my worry is that my total wattage is over the maximum recommended by the inverter. So far Solar Assistant says I never went over 650v on any string.
The panels are Risen RSM132-8-660BMDG, and are bifacial ones.
STC ratings at extra 10% back side gain are: 
Rated Power in Watts-Pmax(Wp) 726W
VOC 46v
Short Circuit Current-Isc(A) 20A
Maximum Power Current-Impp(A) 19A
Maximum Power Voltage-Vmpp(V) 38.23
Temperature Coefficient of Voc -0.25%/⁰C
My inverter is Deye 12kw SUN-12K-SG04LP3-EU. AC-DC rate 1.3
Max. DC input power 15600w.
PV input voltage 200v-800v,
MPPT range 200v-650v.
PV input current 26A+13A.
Am I safe like this, 2x13 panels? If not, how many panels should I have on each strings?
I appreciate any recommendations, thank you.
 
EDIT: I now have three strings of 7 panels. I haven't decided if i would sell the rest of the panels or put another inverter for more energy over the winter.
Thank you all for your advices.

LiFePo4 batteries are NOT like your Li-Ion smarphone batteries.
1. LiFePo4 batteries have 4000 to 9000 charge cycles, depending on model. Your phone battery has 500-800 charge cycles.
They are less energy dense but have alot more charge cyles and are designed to be used 15+ years. 
2. LiFePo4 batteries do not need trickle charging from 90% to 100% like your phone does. LiFePo4 batteries can take the same rate of charging up to 100%.
3. Charging them to 100% allows the BMS to balance them in order to maximize their performance and prolong their life.
4. As long as you cycle them daily it's ok to charge them to 100%.
5. LiFePo4 batteries if stored for 10 years without ever charging them, they degrade about 20%. They still charge and hold about 80% of their initial capacity.
6. LiFePo4 batteries are less prone to combustion and thermal runaway. They tend to be cooler when charging, in comparison to Li-Ion batteries
Smartphone bateries if not charged for 10 years, degrade from about 60% at best, to complete capacity loss, depending on your luck.
 
 

LiFePo4 batteries are NOT like your Li-Ion smarphone batteries.
1. LiFePo4 batteries have 4000 to 9000 charge cycles, depending on model. Your phone battery has 500-800 charge cycles.
They are less energy dense but have alot more charge cyles and are designed to be used 15+ years. 
2. LiFePo4 batteries do not need trickle charging from 90% to 100% like your phone does. LiFePo4 batteries can take the same rate of charging up to 100%.
3. Charging them to 100% allows the BMS to balance them in order to maximize their performance and prolong their life.
4. As long as you cycle them daily it's ok to charge them to 100%.
5. LiFePo4 batteries if stored for 10 years without ever charging them, they degrade about 20%. They still charge and hold about 80% of their initial capacity.
6. LiFePo4 batteries are less prone to combustion and thermal runaway. They tend to be cooler when charging, in comparison to Li-Ion batteries
Smartphone bateries if not charged for 10 years, degrade from about 60% at best, to complete capacity loss, depending on your luck.