Non line of sight (NLOS) 481THz light

My attention is turning back to 481THz (red light) and slightly lower frequency (IR) light communications over the visible horizon (NLOS). From the new QTH there is a good local marker (roof top chimneys on a house in the High Street) for a 6.18km NLOS path to the place I used to go to check VLF earth-mode at limit range. If I can set things on the right beam heading from home,  I then have to persuade my wife to drive me out there after dark where the roads are VERY bumpy and rough - it is way out in the fens - to see if I can pick up QRSS3 signals using Spectran software. This is where I really miss not being allowed to drive (because of my stroke) myself.