Bennie,
Like DGold Guy mentioned it surely wouldn't hurt (no pun intended) to run a bit fat on the main.
There are several other factors to consider when trying to keep the bike cool in that enviornment.
The type of coolant you are running, and the condition of it. The ambient air temp, and was the bike running warm prior to the last trip.
When you line up is the bike idling for an extended period of time between runs?
I realize the question of lining up and "hot lapping" might not be fair, it depends on how crowded the dunes are.
But really, if you were able to make four or five runs up the hill with no cooling down between drags, that is quite a lot of work.
Were any of the guys you were riding with have an over heating problem or was it just your bike?
There may be a several things to take in to account. Have you had the bike out after that trip? ,