The DSSR20 can handle two of those 385W panels in parallel ideally you will have one panel on one side of the roof and the other one on the other side if is not to complicated but the DSSR20 should handle two of those panels even if they are both on the same side directly facing the sun and yes 10AWG wire is excellent for a group of two parallel panels.
You do not need any MPPT as te DSSR20 will already work at max power point with those 120 half cut cell panels (two 60 cell in parallel).
That Victron future will not work with LiFePO4 only with Lead Acid and what happens there is the battery will still be involved in powering the Load as Load will need to be larger power than what you can max get from the panels.
With Lead Acid battery voltage quickly gets to absorption level 14.4 or 28.8V (battery may be just at 60 or 70% SOC) and from there the batteries will take less current than available from panels so you can use the Load output of the MPPT solar controller to connect a Load but that Load will be supplied by the PV panels with different coming from battery or if smaller the battery will continue to charge tho with Lead Acid battery will never get to full charge (not with solar).
With LiFePO4 this strategy will not work as battery will always be around 26 to 27V at almost any SOC and battery will use all the current PV panels can provide so nothing is lost until the battery is fully charged when the solar charger is ordered by the SBMS0 to stop.
You can use the SBMS0 signal that battery is fully charged to divert the PV energy directly (can not be done through MPPT).
The DSSR50 will handle much better your panels and can handle 4 of those panels but the diversion for DSSR50 will be available as a separate device much later probably only early next year.
The DSSR50 I hope to have available by the end of summer.
You should leave the battery to fully charged when the day starts then you can maintain a lower SOC. If you never fully charge then SOC will decrease in accuracy as correction is done at full charge and without that correction all the small measurement errors will add up over time and SOC value will be less and less accurate.
There is no need to get to this level of complexity with PWM trying to match the exact PV production as the LiFePO4 battery can cycle at the top hundreds of thousand of times so all that cycling will have no effect on battery life is like a super capacitor in that sort of use case scenario.
Also your PV array can not be that large in this case just 0.2 to 0.3C but for house heating you need a much larger PV array thus you should be able to use the PV energy directly and separately from battery.