hey there @Meredith_Miller! I'm the maintainer of the LookR repository, I can answer this question.
The limit override functionality in LookR currently isn't operating as intended, and I believe that is a mistake on my part. The issue has been lingering for some time because LookR is, at the moment, a volunteer-run project that is maintained mostly by me in my evenings and weekends.
However, I believe that we should be able to do this in theory, despite the limitations in the project on saving Looks with no row limits. Like always, this will only work for Looks which do not use features which require the Look to load in-memory, including things like table calculations and pivots.
I'd like to invite you to +1 the Github issue for this problem here and if you have any follow up questions I would be very happy to address them there: https://github.com/looker/lookr/issues/11