I agree with you on McManus. Doing this once (or twice) in the group stage each year isn't enough. He's experienced enough now that he should be doing this four or five teams a year.
But in the case of Weatherley, I've alluded to before that we should be looking to bat him between about overs 8 and 16. (Not necessarily for the entire 8 overs, but going in and out at some point during that period.)
He doesn't have the power to finish off an innings at the death, and he'll generally chew up too many balls in the powerplay. But he's more than capable of knocking 1s and 2s around in the middle overs, coupled with the odd slog swept boundary. The problem with that though is that we bat him down at no.5. In theory, as I've said before, that should ordinarily be too low to play that role. If your batting innings has gone well, your no.5 should generally be there at the end; or at the very least, not getting out with 4 or more overs still left. If we're batting him in the wrong place, that is our fault more than his.
Somewhat perversely though, our failures at the top of the order today and vs Gloucs have allowed Weatherley to come in much earlier than a no.5 should. Basically coming in as a no.4 (but with the added pressure of an extra wicket being down, and not too much to follow). That has duly allowed him to play like he can, making reason contributions and at reasonable strike rate, before then moving aside to let someone else finish it off (McManus tonight, Fuller last week).
But we can't find ourselves in a situation where we want the top order to fail, just to suit Weatherley. That's idiotic! Much better to just move him to no.4!