Shaun
If you hit the low fours and you think it will keep dropping, I would keep an eye on it and time it to see if you need to treat it as a hypo. IE i can test before dinner injection, its 4.4 but I know that I can sit steady until dinner time, or i will have some nuts of a slice of meat just to increase it a wee bit but not too much before dinner.
If this is the case, just have half slice toast, bit oatcake etc.
As for treatments, the 150ml cans of coke are good to have about (mixer size you get on planes) and half can of this will bring me up. I used to eat 3 dextro tabs but was overtreating so will usually only have 1 and then test again, I hate overtreating nearly as much as the hypos themselves
The rule is apparently 15g fast carbs, 15 min wait to test, 15g slower carbs
Sometimes depending on number I will just eat a tiny bit of fast carbs, then have something to eat right away, Dont always wait 15mins either (only 5 months dx, still get worried a bit!) so tend to test bout 5 mins later
Still, you seem to be really doing well already, Onwards and upwards!
x