A light integrator measures the amount of light being outputted instead of measuring the exposure time. They are better so that you can start your exposures even when the bulb is cold, otherwise yu have to light the unit and wait until it stabilizes.

Visit www.olec.com and drop them a line, they might be able to advice you what is the best way to go for your unit. BTW make sure they still have bulbs and spare parts for the unit, if they do then it might be good to buy at least a couple of bulbs.