Mr Hp I agree the less tip the better. We tip our hive boxes completely on there sides when checking for swarm cells. 90 degrees as shown by Ian Steppler. Of course they are not being moved around and bumbleing along, but there again, in fairness to (some) of these lift designs, they are not being transported vertically as might have been seen in one of the design videos above.
Actually some of these designs are only tipped at 30 degrees . Some even less. We should be just fine? Less the feeders. Plus remember, when rotating brood boxes, adding queen excluders, adding boards for separation of bees from honey supers, complete inspections, these lifts hold the raised boxes pretty much level. A real back saver?
For removing honey boxes for loading and extraction this will make the job a breeze and should not be any question of a problem. Especially our back! lol
Taking into consideration these lifts are designed for the hobbyist, and small commercial, namely ones with bad backs in particular who wish to continue enjoying bee keeping, (and not large enough to justify investing in an easy loader), hopefully many more years when nature says it times to quit. These have to be much help giving the beekeeper a new refreshing out look on beekeeping? Just food for thought.
