most efficient? Travel agent. But you’re asking too much - even layering in CapOne? Just focus on draining what expires first (and transferable is tricky).

We’ve been super ultra lucky with 2+2 split itineraries. For bigger trips, I book it all together. For an intl trip earlier this year I tried what you’re doing and nearly got stranded in South America.

you start doing this - as I have - and you risk aircraft changes, schedule changes - and near departure, WX/MX and IDB…

ps - we got skymiles for my kids as young as allowed. I think at 2.