Each woman is different and will react differently to a lack of sleep. Unfortunately you won't know how you react until you try...
I don't sleep particularly well. Most nights I'll go to bed around 10-10.30, I'll lie awake for an hour or so, wake again at around 1, often again at 4, and then sometime between 5 and 6.
If you use Fertility Friend software, the temps that you record after
hrs sleep you enter as 'sleep-deprived'. It then shows these temps with an open instead of a solid circle. You can then instantly see whether the temps may have been affected by your night-waking.
Feel free to look at my charts - the first month, I followed these instructions to the letter, hence lots of open circles. I was temping every time I woke up, just in case. I learnt that my temp doesn't actually vary very much between 5 and 6, but for every 20 mins or so I sleep after 6, it jumps up. So now, my alarm is set for 6am every morning, but in practice, I temp any time I wake from 5 onwards and use that temp. If I wake between 3 and 5, I temp, and note it down in my diary. Then if I get a full hour's sleep (ignoring the 3 hour rule) before waking again, I use the later temp, noting sleep-deprived, and if I don't, I use the early temp, again noting sleep-deprived.
Seems to work fine for me. This month's chart is wonky, but that's becasue of the after-effects of a chem pg, not because of the temping.
If you have any more questions, ask away or pm me!