The inspiration for all my optical experiments came from Stuart Wisher G8CYW who did a great series in RadCom a few years ago.
There was no sign at all of the TX beam in the sky. All alignment used dead reckoning with some panning at the RX end to find the TX.
Using free PC software and QRSS3 helped as bandwidths as low as 0.37Hz were possible.
When fitter I want to try infra-red LEDs instead.