I got myself into a routine. Even if I didn't have to be up at my usual wakeup time, I would have the alarm set, and take my temp and then roll over and go back to sleep.

If you know you will always be up at a certain time to put Matilda's feed through her tube, you could set that as your temp taking time. They do recommend 3 hours sleep, but if you are only up to switch her pump's alarm off then you are likely to be still half asleep and not really disturb your sleep IYKWIM.

Give it a try for a month or 2, and if it gives you decent cross hairs, and seems to line up with the other signs (OPK, CM, Libido, Cervix position) And do the course it send you, that really helps