I have been injecting insulin for almost 20 years now. I take a slow reacting (Lantus) once a day, and a fast reacting (Humalog) multiple times a day. My sugars have dropped multiple times over the years after getting high. Mainly because they were on the low side to start with. If I don't wait at least 30 minutes to smoke after taking my Humalog, my blood sugars will drop (and I mean drop hard and fast) every time. As long as I wait over 30 minutes, I'm fine.
My suggestion to you would be eat a small snack right at bedtime to elevate your sugars slightly before falling asleep to avoid any problems.
I'm going to try growing Blueberry because of the effects its supposed to have on Diabetes and see how it works on me. I'm hoping I will be able to cut back on the amount of insulin I take. Time will tell.