Yep nothing wrong with doing that at all.
I'm the same as tracey with a little snack, but experience tells me that it's a one off for me any way...
As bev says, 3am and 2 hours are both good starting points, between 2-3am for most is the lowest ebb for all hormone production (ask most nightshift workers, most will say between these hours is when they struggle to stay awake) the 2 hours doesn't work for me, I change around an hour before but that me, I do like to be the odd one out🙂
Basal testing is a pain to do, specially at night but I do have a little tactic called hubby, I get him to wake and do one or two tests for me (I acutally can sleep through having my finger pricked) and he will only wake me if needs be..