Simple mathematics Eric. Both the 35L6 and the 50L6 draw .15 amp. Thus the 35L6 will actually run cooler. But the 35L6 plus the 82 ohms resistance will generate about the same heat as the 50L6 alone. Where is the gain? The additional heat is above the chassis and dissipates easier in the atmosphere to warm that frigid “cold air from Canada” as they say in weather reports in the States (with all the CO2 released by tar sand industry I wonder why they still make us feel responsable for cold air…). Back to the subject, the old 82 ohms resistance is more prone to failure than the tube.