It really is worth getting at least a spare tyre and keeping it in the boot/shed/garage. When puncture time comes, these are not particularly easy tyres to get hold of. Very few tyre places seem to stock them, which means ordering for next day (if you're lucky) and paying top dorrar.
Not wanting to hi-jack your thread, but I woke up the other day to find my offside rear flat. The tyre weld worked well enough for me to get to a tyre place. Initially they said it couldn't be repaired because tyre weld had been used. Some talking, and 20 minutes later it was repaired. However, because it's so close to the sidewall, and was caused by an actual cut, I ordered a new one anyway and will be having it fitted tomorrow. Not worth risking a dodgy tyre, especially living in Germany and doing 120+ most days.