Over the counter demazepam here. I save it for when I know have to get a good sleep, if my pattern has been off, or sometimes to try a reset my body clock. I was travelling with friends on overnight buses in Argentina years back and few had a little stock from previous travels. They were sharing. My last trip back to the UK, I was due to land ad 7:15. So at 11pm UK time on the plane, I necked two after a couple of drinks and woke up just before landing. I wasn't 100% steady on my feet, but Jetlag was not a problem.
I too have to curb the coffee intake. No more than 3, usually two, never after 4pm. Veitnam is Coffee shop culture. Everyone one is, lets meet for coffee after work. really coffee 'after' work. They don't get it at all, and will be up often before 7 am, but it's also a siesta culture.
My New years resolution I post above was to train, but resistance training late in the day, seems to kick off hormones that stop me sleeping. So I can only train in the first half of the day. Cardio helps though, I always seem to sleep well after cardio.
Have you tried evening walks, cycling or swimming. That may keep you under after you've nodded off. I've found some beers, will wake me up after I've fallen asleep. I've learnt to avoid those, but you say you don't drink.