No reason to discard perfectly good feeders. Remember that in the wild, snakes catch whatever they can- sometimes on the large side, sometimes on the small side- but rarely "perfect". So if some feeders are way too small, you could double them up (feed 2 per meal) but better* than that would be to just feed small ones a little closer together, & the larger ones, feed with more time between meals to digest- see? *One reason it's better NOT to feed 2 items per meal is that many BPs won't accept 2 items- they'll quit after one, no matter what, so then you're just wasting food. And you don't want to accidentally feed too much either.
The BEST way IF you feed 2 items per meal is to have them both thawed & ready to go- you don't want much time to elapse between the time a snake eats the first one & the time you offer the second- for BEST results. Otherwise, it's more likely they won't take the second item, OR it's more likely to cause digestive upset if too much time goes by- & neither of those are what you want. Snakes get "pumped up" about eating- but after the first item, some get shy & are ready to go hide, & they'll refuse a 2nd item. They're most likely to take it if it's right there for them to grab as soon as they finish the first.
I'll let others here (that keep BPs & that also weigh their food) address what size a snake like yours "should" be eating- but don't be afraid to NOT stick to an exact schedule for your snake- schedules are just there to help keepers remember when it's time- the most important thing is giving your snake enough time to digest. A bigger meal- just allow a few extra days before feeding again, since over-feeding isn't good for them- and if the prey is smaller than usual, watch for your snake to be hungry & ready to eat again a bit "early".
Also, it's best not to suddenly give a larger item (just "in case")- I'd save those largest rodents for last. Looking good, by the way.
