Definitely book your initial 3 FPs per day. You don't "need" to, but why wouldn't you? They're free, it's easy to book them, and they're definitely a time-saver, even at relatively slow time of the year. But there's no need to stress about it, unless you're going for a really sought-after FP like A&E (sounds like you probably aren't). It's only stressful if you let it be!
As another poster suggested, a good strategy is to hit rope drop, ride standby for the first few hours to maximize your time, then schedule your FPs for later in the day. Or if you don't wnt to rope drop. sleep in a little and schedule your FPs for later. Isn't it worth it to know you have three guaranteed rides per day with very short waits?
FWIW, I went the last week of February last year. It was a "slow" week (crowd levels were a 4 most days) but we were very happy to have our FPs. By rope dropping and using FP, we were able to get tons done!