May I put another point of view? I understand the difference in running barefoot but most of us are not going to do that on tarmac which may be the commonly available surface. That would be a quick route to injury.
I don't think Andy should worry about stride at all at the moment.The demands of what he is trying to do will determine his stride length. Whilst we can watch track runners matching long flowing strides over 1500 metres that will not be likely for most runners at club level. Think of marathon and ultra-distance runners - Ethiopians and people from the Kenyan Rift Valley, for example who scuttle along with a short economical stride, barely lifting their feet above the tarmac, and compare their stride with Usain Bolts! And because running involves hills and different wind direction, stride length will change to accommodate the needs at the time. Just run and relax, stride rate at this level will take care of itself - and change as running fitness develops.