Greg,
For over a year now, I have been running a pair of Nelson NHFM70’s, (roughly 80watt load) and two 150 watt halogens powered by a little 650W genny, that provide plenty of light for most bowls. My genny could stand to run another two NHFM70’s. Mine would have the same globes as these.
These metal halides throw out roughly 4 to 5 times as many lumens as a halogen lamp. A 70 watt MH arc lamp puts out about the same light as a 300W to 350w Halogen incandescent lamp. It is a white light, not yellow like the incandescent lamps. (a little ball of lightening trapped in glass!)
At $105 each, they are a bargain. Mine are worth $170 each.
One of these lamps replace the two lamps that you normally have on the halogen light stands that you get from Bunnings for $25 each.
Saw the pics of Hulley’s ramp. Looks like he has MH lights.

70watt MH at Cheltenham.