Amritwela timings

Vaheguroooo ji ka Khalsa Vaheguroooo ji ki Fateh !!
I recently read in post "Bachans By Gurmukhs" where veer Kulbir Singh ji mentioned about bachan by Bhai Jagtar Singh Ji that one should wake up for Amritwela no later than 2:30 AM and the earlier the better.

Is there historical evidence about it as well? Most of reference material available including Mahan Kosh, Rehatnaamey etc. mention the earliest timing about 1 pehar before morning which is 3 AM (Mahan kosh only mentioned 6 ghari before morning which is 4:30 AM).

For Gurmukhs who have done enough naam kamaai only have sleep of couple of hours and hence for them it is possible to be awake by 2 AM and not sleep again until the day but for an average person few hours of sleep is required and hence getting up around 3:30 - 4 is more reasonable. Or is it better to wake up by 2 AM and sleep again by 4/5 (not sure how fresh that kind of learner of initial stages be)?

Bhul chuk maaf kar deni

That's how I personally do it. I wake up in the morning around 3:30ish, and I go back to bed around 5am, after doing nitnem and abhiyaas. Since I go to school, I get up again at 7am to get ready.
I sometimes think that when I work late into the night, it's really hard to get up so early in the morning. I get 3 hours of sleep, have to wake up, and then about 2 hours again. This isn't healthy, because I feel that I don't get the proper rest this way, yet I continue to get up.
Sometimes I tend to zone out in class, or start to fall asleep because I'm sleep deprived. Also, I feel that this affects my studies as well, because I cannot pay full attention in class. Not sure if this is okay, as long as I'm following the Gurmat Principles of waking up everyday at Amritvela.

Is it okay to get up later in such cases? Or would that be considered a "violation" of the Gurmat principles (waking up at Amritvela)? Sometimes when I'm really late, I'll get up at 6am. But I'm sure that doesn't count as Amritvela.

So what should I do? I try to go to bed early, but especially around this time of the year, with exams coming up, sleep is so hard to come by.

Vaaheguru Jee Kaa Khalsaa Vaaheguru Jee Kee Fatehh!

Vaheguroooo ji ka Khalsa Vaheguroooo ji ki Fateh !!
Veer Kulbir Singh jio or other beloved veer jio, please advice your suggestions based on what you learnt from sangat of Gursikhs. Also veer Sukhdeep Singh jeeo, any reference from rehatnaamey about timing?

Along with Bhai Randhir SIngh Ji I have heard some writing like
Panth Parkaash mention to get up around 2:30( sava pehar)

ਸਵਾ ਪਹਿਰ ਨਿਸ਼ ਕਰੇ ਸ਼ਨਾਨ, ਬਾਣੀ ਪੜ੍ਹੈ ਖੜ ਪੱਗ ਬਧਾਨ। (ਪੰਥ ਪ੍ਰਕਾਸ, ਪੰਨਾ ੫੪)

ਸੱਚੀ ਭੈ ਭਾਵਨੀ ਸਹਿਤ ਨਿਤਾਪ੍ਰਤਿ ਸਵਾ ਪਹਿਰ ਰਾਤ ਰਹਿੰਦੀ ਉਠਣ (ਜਾਗਣ) ਦਾ ਉਦਮ ਬਲ ਧਾਰੇ ਤੇ ਪਿਛਲੇ ਪਹਿਰ ਵਾਲੀ ਰਾਤ ਰੂਪੀ ਅੰਮ੍ਰਿਤ ਵੇਲੇ ਦਾ ਸਾਵਧਾਨਤਾ ਸਹਿਤ ਆਨੰਦ ਮਾਣੇ। (Gurmat Bibek, 99)


In Shahhed Bilas there is mention that Shaheed Bhai Mani Singh Ji would rise at 2:30
ਸਵਾ ਪਹਿਰ ਨਿਸ ਰਹਿੰਦੀ ਜਾਗੈ I

But I have also read in the rehatnamey where this mention of getting up on the last pehar of the night ( eighth pehar). Example Prem Sumarag rehatnama.