Raft warping (Makerbot Replicator+)
I'm not sure I am reading your post correctly, but if you are doing a batch of small prints, I would recommend to space them enough so as each of them has its own mini-raft, rather than all of them sharing the same large one.

If you are using cura, you can tweak how much the raft goes past the footprint of the part.  Unless you are printing very small parts, you don't need that to be a lot.

In general, you should think to a raft as a print in and by itself: the larger it is, the more prone to warping, although the way filament is layered with gaps makes the raft bend and warp a lot less than a regular print of the same size.