| Never used 207's but my experiences with the previous Avon range on my 750ss as follows:
AV39/40Supersport - excellent for thrashing around, highly recommended. Great for grip - rubbish life, knackered the rear in less than 900mls - (on a 750ss remember!)
AV35/36 (the hardest of the 3 versions in the range) fitted in the hope of longer life. Didn't like them - very insecure feeling when cold, even warm the front seemed too hard and rather skittery. still on the bike when sold but I reckon the rear would have lasted about 3000mls.
Probably the best combination would have been AV39Supersport front with a std AV40 rear.
For reference, I reckon the BT010 was better as an all-round tyre ( the rears did ~2,000/2,500mls BTW) but for track days/ 'thrashing' I did like the AV39/40Supersport.
Dion
Oh yes and they are cheap! | 
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