I just thought of this...the heating transformers were configured for 36w T8 but now it's used for 58w T8. Would the filaments require higher voltage or current?
When they run on the rated current, they need no additional heating supply at all.
They need the electrodes to be preheated for start, but then the ballast current into nearly short circuit isway just what the lamp need, so no transformer either.
For RS style operation the tube have nearly no window between maximum voltage when the lamp never ignite with cold electrodes and minimum voltage for reliable ignition with hot electrodes, so it would either instant start in some more favorable condition (hot, dry, metal work nearby), so would have short cycle life and/or don't start reliably in conditions less favorable (lower temperatures, humidity,...), what would cause their usable life being short too (slight electrode wear and they would start less likely).
So the only mode of operation for high cycle life would be "programmed start", so first preheat the electrodes and only after some time apply the voltage for ignition. And that exactly is, what the electronic starter does with the regular simple "preheat" circuit, even without any heating transformer or so. And that is the reason, why you won't find any designed for the F58T8, nor any other krypton lamp...
Otherwise the diference between lamps is only in the current: The 58W lamp would need 30% higher currents for the filament...
