I find for me taking both metformin and glimepiride with my late evening snack, works well typically 9-10pm then 9am in the morning I tailor my medication to the sort of month I plan on having, for the next 2 month I'm using the above, but then I plan to go to the gym in 6-8 weeks time at around the 4am so once I've recover from surgery I'd switch times to 3am and 3pm, I normally take them 5-10mins before food, as that is normally how long it takes me to get the food ready.
I do tend to just trail and error, until I find what suits me, I've only been back on metformin for the past month, I'm also taking gilimipride at night which I find helps avoid the liver dump, but I'm extra careful to make sure I eat well enough to avoid the possibility of a hypo as glimepiride is a sulphonylurea.