Zimagold... Dont worry
My car is also not suitable for flat towing, and I do a 10-mile commute each way every day. My car is automatic!
Most days, I get 9-12% engine OFF coasting at a maximum of 38mph... Which is just over 2 miles a day. And I also used to do the car-park-roll down thing dozens of times until I moved to another car park at work.
So, my car says you can only flat-tow it for 20 miles, at 30mph, it EXTREME emergency (unless an extreme emergency, it needs to be towed with dolly wheels). I have done lots of 38mph engine-off coasting, for up to 1/2 a mile at a time! And so far, no problems have occured.
A word of warning : do not copy me
I can easily afford to put a new transmission in, and, more importantly, I have a manual gearbox in my garage waiting to go in in the next few months. And if I get gearbox faults I would be prepared to drive it to destruction as long as it still went forward before replacing the gearbox
. For any coasts above 38mph I do engine-on coasting. I also rev-match prior to going from neutral back to drive, and my gearbox is one of the ones that doesn't mind going D-N-D-N all day long.