Solar Maximum watt for solar boost 2000e

[AST]

hi folks
I have a solar boost 2000e with a 100 watt solar panel. I need more juice so I am thinking of adding more panels (but really don't want to change the controller).
1- So what would be the maximum wattage I can add?
2- I am thinking of adding 2 more panels (100 watt each) for a total of 300 watt, would that work?
3- Can I actually add 2 200 watt panels for a total of 500 watt still with the existing controller?
4- should I connect them in series or parallel. From what I have been reading series make more sense.

Thanks in advance