That's great!
Although I don't think I'd change the wattage (larger dissipation ???) of the resistors. Going to a metal resistor is a good idea. If anything I'd raise the resistor(s) off the PCB using some ceramic stand-offs (or something similar) to allow for more air-flow and thermal radiation.
Whatever can fit in that tight space some resistors are much underated and get to 65 degrees easily.........poor design for a power supply........so long thanks to both for now
Thanks to technology new resistors are rated higher and take-up less space, as we get older we cannot even see the colour band. Received the parts and proceeding with "re-vamping" supply circuit. Next I will look for a slim DC fan and install it to cool this portion of the board. As last optional upgrade I may add my own Phono preamplifier, tapping into one of the available inputs......regards until the next adventure.
More Watts in less space is Higher Temperature. As you note, the new resistor is designed to stand the heat, but our decades-old PCBs may not like it.
What air-cooled resistors need is AIR. The tip to leave leads long and set the resistor high off the board is one way. (Yes, a fan is another way.)
There's a similar situation in US house wiring. Early rubber insulation was marginal to 60 deg C. Postwar plastics were good as high as 90C. But for "small" (in wall circuits) wiring we must treat it as 60C because many of the devices (receptacles) are not good for high temperature.