When working a solo kata, like 31-jo kata, into your routine, you need to be aware that the best way to utilize this kata is as a reminder of the paired-kata that you have already practiced with a partner.
Application must come before solo kata, or else you will have no guideline for what the solo kata is supposed to become and what it is supposed to do for you. With no prior experience of the application, solo kata is very subjective and vulnerable to our fantasies about what we might be doing. If you learn the solo kata outside of the context of application then you can easily come up with some retarded, imaginary applications that then become written in stone because of your solo kata practice.
Instead, if you learn and practice the paired applications first, then the solo kata becomes an aid to visualization and review of that material when you do not have a partner.
So, if possible, you should learn the applications with a live partner before you spend much time on the 31-jo kata - or at least learn application concurrently.