Choosing charge controller

I have received so many different opinions. I need to get a MPPT for my system but not sure which one. I currently have 4 ecoworthy - 100 watt panels but plan to upgrade to 6-8 at a later date, still 100 watt. I have a 2,000 w inverter with built in transfer switch, charger, 30 amp shore power and 4 12 v 100 ah lithium batteries. Would I need the 100/50 or 150/35 mppt?

Take a look at this:

Thank you! so it looks like I can get the 100/50 if I want to add 2 more panels. Thats about all I can fit on top so if I need more I would have to get portable and another charge controller