My friendly opinion is that ... in being “vague,” you are also being abstract. Perchance you are seeking an abstract, therefore universal, answer to a business question that is almost-entirely: “it depends.”
Fact is, questions like these really can’t be meaningfully “abstracted away” from the business cases in which they sit. When you say, “speed matters, a lot ...” well, I just don’t know what that means in terms of revenue. Likewise, I don’t know whether “speed loss ‘less than 50%’” is something that will cause my Star Customer™ to “feel ill-used™” or not. And this, in the world of Business, is all of what really matters.
Dr. Moore tells me (correctly, so far ...) that “I only need to wait 6 months,” but my Star Customer (upon which my salary, and yours!!, utterly depends) might not wait that long. Therefore, this is no longer a pure-programming or pure-Perl question.
You need to elevate this question, having first fully-developed the business case, to those persons within your organization who are responsible for both tactical and strategic business decisions ... before deploying this change. You appear to be presenting an issue that (a) has obvious revenue-impacting potential, and that (b) therefore is “not simply a technical issue.” The “correct” action in this situation has
precious little nothing to do with Perl.