Ryanair Baggage - Family Plus Option
 

2 adults, 2 children traveling. Wouldn't I be better booking 2 separate itineraries (1 adult + 1 child) for the Family Plus option? It says "1x 20kg check-in bag, 1 large Check-in bag for your family trip." Cost is $42/per person. However, I read the 1x check-in benefit as per family. Booking 2 separate reservations would get me 2x check-in bags vs 1x if I book all 4 on the same itinerary?

Yes, if you buy Family Plus you'll get one 20kg check-in bag for the entire group. Plus a 10kg check-in bag for everyone (adult/child) on the booking.
Booking 2 separate reservations, both with Family Plus added, will indeed get you 2x 20kg check-in bags in total. However the surcharge (per person) you pay for Family Plus is higher on a 2pax reservation than it is on a 4pax reservation. So, depending on the extras pricing your particular flight (it's all dynamic pricing with Ryanair), it may be cheaper to simply add a extra 20kg bag while booking everyone under a single itinerary.

If you don't need the 10kg check-in bags it's very likely it would be cheaper still to not take Family Plus at all, and book only the cheapest fare adding only 2x20kg check-in bags.

Thanks for the tip. You are correct that piecemealing it together ends up cheaper unless you really maximize every benefit from the "package". So many combinations to think about..