Dividing paper after Reject & Resubmit decision In a recent manuscript, we used a first principles calculation A and used it to explain experimental results B. A and B are based on existing methods, the novelty primarily lies in combining them and going from theory to real world application.

The reviewer gave several comments (fair &amp; helpful), one of them being to divide the work into A and B. The decision was Reject &amp; Resubmit. We (the authors) are divided on:


Submitting A as a letter (short communication) and B as a full paper to the same journal, together, explaining the changes to the editor and attaching response to reviewer.
Submitting A as a letter to a new journal and B as a full paper to the original journal, giving response to reviewer only to the original journal.
Submitting an edited but undivided paper to a lower impact journal.


Which of these is the optimal option?

*Additional information:

The original journal has perhaps 10% acceptance ratio, the lower impact journal closer to 40% (anecdotal numbers only).

Besides the division, reviewer comments are significant and there is some chance that we may not be able to satisfy all the suggestions.

In this field, A and B are generally treated as separate domains, though this is changing now.*

EDIT: Clarification about letter and full paper:
For the journals in question, a full paper reports new, original results, typically without stringent page limits (but conventionally 5000-8000 words). A letter on the other hand reports brief results of immediate interest. These often describe a breakthrough that may not be fully developed, but which opens up avenues for further work. These letters are strictly limited to 2000 words and have a cap on figures etc (typically 3 max.).
This is common for very novel, high impact findings, particularly when the issues are complex and have both theory and application. What I’ve seen work is a shorter theoretical work submitted to a high impact journal that touches on application (often, the work references this ‘submitted’ or ‘in preparation’ work). The longer work is then submitted to a lower impact journal, sometimes just because the page limitations are more forgiving. 

This of course works best when you can tell two separate but related stories that feel complete on their own. If you and your coauthors feel like such separation is forced, it may weaken rather than strengthen the effort. 

I’d say your #1 might be unlikely unless you get buy-in through discussion with the journal. #3 may not do your work justice. I’d lobby for #2 based on the limited information available.