I've not heard that a ground level landing board helped heavy bees. That's a riot! In fact, I don't believe there's any credible evidence that a landing board helps or makes the bees more efficient.

Nature made them to choose hollow trees with small defendable entrances. Bees who miss the entrance and bonk their noggins on the tree would soon clear out of the gene pool.

Give the bees some credit for doing things right.

Landing boards are simply to make beekeepers happy. They must confuse bees with airplanes who need runways.

There is a very well known beekeeper here in Western North Carolina, 300+ hives, smart guy, and when I brought two hives without landing boards (I was buying bees from him), lectured me that landing boards "are important" and that bees laden with nectar or pollen "expend far too much energy if they miss the entrance and have no landing board to keep them from falling". He felt this would shorten their lives. On the other hand, I've watched these two hives carefully and 99% of all bees fly right in. Once in a while a bee will have to hover.

And regarding the height of the stand, for the bees the higher the better. In nature they rarely build close to the ground. For the beekeeper, anything more than a foot or so starts being hard on the back.

Yes, it's very well known that landing boards are critical for the bees to land. But it's not true. I think your own observations bear that out.

Nor are large 3/4" times the width of the hive entrances important. All mine are on 3/8" all year long. Even then, some much prefer the 3/8"x 2 1/2" top entrance to the point that I have had hives try to popolize in the normal entrance. Doesn't seem to hurt production any. One such hive put 5+ supers of honey away only using the small upper entrance (The bb is screened and they have a ventilated top and showed little bearding and no tendency to swarm).

My 5 frame nucs all have a 3/4" hole for an entrance now. They do much better than those that had a normal entrance and landing board.