What do you always want to ask a structural engineer for? Every manufacturer has instructions, just follow them, although they really mean well with the tolerances.
But if the concrete mixer can’t reach there, how do you want to get sand in at 45m x 2m x approx. 0.25 m3, by hand? Well then, good luck.
We built about 50 meters of wall with Dad and partly on the boundary with the neighbor, it’s damn hard. But there were stages spread over the year.
For the foundation, we had concrete delivered. For filling, depending on the position on the property, we had dry concrete delivered with a 4-5 hour delay and filled the hollow blocks with it, so to speak. But it only pays off from 5m3, otherwise you pay extra.