Driving on a setup like this is more of a low and slow mentality... you are not performance driving on a setup like this. If you do you will risk the tire failing prematurely or coming of the rim. The same goes for over sized tires. I reccomend following the tire manufacturer specs. However, a knowledgeable tuner/driver can drive on stretched tires without major problems... I have driven up to 15k miles on stretched tires without incident. Its called being responsible and not pushing the car to its limits or trying to push the tires to the limits.
I hope this answers your question
