Next major mistake turned out to be the same issue, too little space between the walls for any commercially available T5 lighting units that could offer more than 2 bulbs which as I hoped to keep sps would not be very useful.
My brother took me down to EECOL for a visit and I came away armed with commercial 48" T5 ballasts, 8 of them. It turned out that despite the fact that I only had about 10" of space between the walls above the tank I could fit 4 of the commercial ballasts side by side allowing a total of 16 x 48" 54w T5 bulbs over an 8' length.
Better still was the cost, saved a fortune! Bolted together on an aluminium frame and connect to plugs the light was ready to go.
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