You can hit 200 no problem as a free player, I do it , so that 's good news.
You've got to do all 5 attacks every day. I totally understand looking at your phone when it's close to payout time and thinking, "I'm 315, I have two more attacks, the best I can hope for is to finish ~220, so why bother?" But you have to do those last two attacks, because every day you fall back overnight a little less than the day before (on average) and over time finishing 220 becomes finishing 210, then it becomes finishing 200.
If you notice that you drop a whole lot overnight, consider using Darth Maul as your leader for the final attack of the day unless you see a sea of R2-D2s in the teams you go up against each day. If you have Resistance for Galactic War, it's worth considering just doing the last battle with them--they're not great on defense, but every now and again the AI handles exposes correctly and brutally annihilate a team. Not all the time, but just often enough that attackers might skip over you for easier targets.
Everything else folks have said above is totally correct.