If all of the tubes are tied to a common ground they should all start at once. Another thing that you should do, if you make a unit with the bi-pin holders, is to place a sheet of metal at the top of the box, behind the tubes. Or, alternatively, just lay a bare wire over all of the tubes at the side.
Originally Posted by Monophoto
A unit built from two-tube commerical holders does not need the sheet metal or the wires since you have this already in the metal holder. Just be sure to ground all the tubes. I have a twelve tube unit of 48" tubes made from commercial two-tube fixtures. All of the tubes are tied together, including ground, in the power outlet. Every tubes comes on at the same time in this unit.