We have a diabetic cat.. whilst a bit daunting at first you soon settle into it. We've been doing it for about 5+ years. Obviously might be a different routine to ours but we have to inject him morning and night and only eat prior to injections as they bring his levels back down after food and keep them fairly regular till his next feed.
You can use a human diabetic monitor - we got ours from boots.. not quite as accurate but our vet said it's pretty close.
We've also had a few instances where he's had a hypo (Where his sugar has gone far too low after insulin).. but there been approx 3 times in the whole time and now we know the signs it's easier to look out for.. probably easier in dogs as a bit more active. (Extremely lethargic).. with cats the use of honey, treats, and higher sugar levelled food brings them out of it... So if you decide to change his food to more suitable food with less sugar - maybe just have a high sugar pack on the side just incase you test and find he needs it.
Ask your vets the levels he should be within so you know what to look out for if your dog does get too low
Hope this helps