I mapped out the required work, broke it down into sub tasks, and then based on my experience of how long similar things have taken in the past, estimated the required number of people that would be required to do so. I also am always extremely reluctant to assign any fewer than two engineers to a project; code review is incredibly important and without making sure that it is accounted for in resourcing requests, projects can go and do go absolutely nowhere.

Bear in mind there is an element of "undercommit and overdeliver" in my proposal; I expect that we would also be able to achieve something else in the allocated time, but I'd rather make a commitment to something I'm really sure we can achieve, than make a commitment to something we might be able to achieve then not achieve it. I should note that "undercommit and overdeliver" is a strategy endorsed by Lila!

I should also note that I have since adjusted the magnitude of my ask; 1 FTE UX designer (down from 1.5) and 0.5 FTE QA tester (down from 1).

I'm not sure how else to answer this question without literally brain dumping everything I wrote down into an email. Did I adequately answer you?

Dan