I do corrections before bed. My ISF is 66:1, and my target is 92, all day long. I am dreading the day when I will inevitably have to rework those numbers... Since switching to the pump, I can't think of a time I've woken up low, except after drinking, so nighttime hypos are not a huge concern for me.
Rapid acting insulin is much more predictable than long acting insulin. With lantus/levemir, you can get variations of up to 40% in efficacy - with humalog/novolog/apidra, it's more like 10% (don't quote me on that.) So correcting highs overnight on MDI, when you know you're less aware of lows because you're sleeping, can be dangerous. If she's not dropping down much below 200, I would probably try out a correction - but that means getting up to test overnight until you're sure she's not likely to drop too low.
Is Riley's target 150 all the time, or just before bed? Also, do you know why she's usually at 300 before bed? Is dinner especially carb heavy, or does she get less exercise after dinner? Does she need more insulin with dinner? or is she just sometimes high, not always? It might be that instead of doing a correction at bed you could lower her I:C ratio at dinner (more insulin) a little and see the 300s less often.