Yeah I'd do 3-4 days maximum. Depends on the wear also, but the heat cycle effect is the biggest factor. If it's a scorching day and you're on an abrasive track, riding like Mick or something, the tyres might not even last for the 8 sessions... GPR's will be better for the heat cycling, as they are road biased so will be able to cope with that more easily, unlike the GP's which are track orientated...

I accidentally bought some cut slicks on ebay, KR106 and 108's... Hmm!
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NSR300R - Why did i ever have a 250...