I used to do roughly the same hours as those, I kept my insuin as normal, ie did at 07,30 etc, but in those days i was on my really nice old insulin that spiked, so new when to watch out, i was always lucky as usualy could nip to the loo when i wanted and check things.
if very physical may need to reduce insulin, but i kept the same hourse of administration.
hope this helps a little