Thanks Ty, would there b any benefit to rigging up pulley to light mover to move bulb up n down n traditional vertical with 4-5 ft plants surrounding bulb n o shape?
Yes there would be a benefit; I ran a single HPS thouie in a vertical silo, the dimensions I chose were 4' tall (height of the fencing) by 4' in diameter (two panels, each six feet long). The middle got cooked and top and bottom got inadequate lighting.
Option one; two 600W HPS lamps, stacked.
Option two; move the HPS lamp vertically about 3', as you suggest. I've seen quite a few grows on various forums that do this quite successfully, some even use a light rail and two silos, so lamps rise and fall opposite one another and balance the load on the light rail!
Option three; add two more panels and a second thouie. I did this and the diameter increased to about 5'6", which solved the overcooked problem. The second thouie did a decent job... but honestly there was a need for three of them.