Posted By Ron Hunter A retractable pneumatic or hydraulic bed (or column set)incorporating ball-rollers would take the weight and allow for easier set-down and adjustment.Power or gearing could also be applied to push/position the workpiece against the corner pins, perhaps in conjunction with laser alignment. Much of the manual effort and intervention could be effectively designed-out? The 4ft high cover and posture problems associated with that is surely highly questionable and one could envision some modification to allow adjustment or hinging whilst setting operations take place (all fully interlocked of course). Difficult to answer precisely without a fuller picture. A determination of what is "acceptable" has to be measured against what is "reasonably practicable" in terms of mitigating risk - i.e. Risk Assessment!