Hi PT,
MS web site
800watts at 12Vdc operation maxes out a 60amp controller
1600watts at 24vdc operation maxes out a 60amp controller
You might want to go 24 Volt house system if you have room for 1250 watts of array - A little bit of headroom in the controller is always a good thing
Where are you getting a difference between series connected Vs Parallel connected panels?
Watts is Watts - as far as I know
So long as you are within the MAX input Voltage limit - that system you listed has a limited 80Vdc input
You know as well as I do as soon as you remove the awning you will find a need for it .......