'it is normally accepted that one dose has an effective time cover of 8 hours'
8.5 hours is the average time it takes for gabapentin to work through the body (metabolise). This means that some dogs will take more time, some less time. So part of tweaking individual SM medication is to see how long it takes before your particular dog starts to show signs of discomfort, as a symptom that they need another dose of gabapentin. Some dogs will go a long time and manage well on gabapentin x 3; others will need a boost every 6 hours or so, so will need gabapentin x 4, even if it may be the minimum 100g each time. The important thing with gabapentin is to give blanket coverage, keeping up the level throughout the day.
Kate, Oliver and Aled
I am not giving 4x/day. Only 3x (100 mg). The doses are 8 am (when I wake up), 5 pm, and midnight to 1 am (when I go to sleep).
I am giving omeprazole around 9 pm, and rimadyl around 2-3 am "as needed" which seems to be most nights. I'm not sure the rimadyl does anything.
Edit: just realised that Scarlett is receiving 4x/day. I assumed the question was directed at me.