Another thing to consider is the potential availability of EC during the 24 hour checkin period. This coming Saturday, I'll be on a CR9 to BDL and, even with less than 4 days till departure, I'm still the only one in the EC section. Other flights can get filled up quickly, since literally anyone can buy it at the time of ticketing (or afterward). I'm traveling with my family during the holidays, and the EC sections are already mostly full on our flights, so I secured them for us by paying the discounted FO rates (I was still FO at the time).

Of course, there is the likelihood of a few complimentary upgrades on one or more of the segments, but even if that frees up some more EC seats, it's likely that they'd be sporadic, not clustered together. I would weigh the cost/benefits of each choice. Depending on the routing, each segment could likely be $15 to $50 with the FO discount.