Just wondering if that 2 hour mark low point is consistent enough that it might be as simple as x-hours after last significant meal? Not that I could suggest any alternative strategy, or would want to encourage any mucking around with pre race regime at this late stage!
burned up glycogen and switch to fat burning, pretty normal
Maybe the answer is fat loading?? Eat lots of ice cream?
Fat adaption may help, there are those who think it works and others who think it's better to just train and not try and learn to burn more fat. It takes training for your body to adapt to burning more fat and supposedly you will run slower during this training because you don't have the glycogen to use so will be getting less aerobic benefit (I think this assumes you will be training close to your aerobic limit).
If you are burning through your glycogen in 2hrs then you're working too hard for a longer rogaine. Ideally you need to be lasting 6hr+ before getting to the low point or probably even better is to pace/train yourself to be mostly burning fat and replenishing most of your glycogen stores as you race.
If you don't get the low point then you're pacing yourself better. Alternatively you could just accept the low point and hope it eventually passes and hope that the extra speed at the start outweighs the slow down.
Talk to that coach, I'm sure he has lots of good info.
Probably a little bit of its just going to happen and not going out as hard. I think the plan will be not to go out too hard, same with last weekend but that all went to pack when it was a straight forward course with three fast teams together!!