Blackwood is easy going on tyres in the normal config. Seems to be a bit tougher on them in the reverse config. You'll be doing about 45 laps for each hour I'd say. So you'll need 1 - 1.5 sets of tyres for every hour you run round there
That's just a ball park figure though. It does depend a lot on the setup and the way you drive. If you lock the brakes all the time, run too low a ride height, have too much understeer they won't last as long. If you overdrive (slide around too much) and apply more than the necessary amount of lock they will also wear out quicker.
So practice being fast but without really pushing, work on a setup by doing lots of long runs and you'll be in good shape for the race,
Endurance racing really does require some dedication because of the long stints you need to do in testing. Its always best to know exactly how many laps a set of tyres on a particular set will give you. That way you're not worrying about it during the race.
Good luck mate. You need some in enduro. Chance of a disco is high and the battle to keep concentration is a tough one too
I think they rub and wear that way or they lock when you hit bumps as the suspension grounds. I remember I had problems popping tyres all the time the very first time I tried to make my own set. It was very low.
Come to think of it though I never resolved the problem with that set cos someone else gave me a good set and at the stage I was only too grateful for it. My conclusions about the tyre failures at the time could have been wrong.