Gerry

the relay board is a simple alternative to using transistors that some will prefer
( as always the best solution is the one that works for you )

the relay board has the advantage the outputs can be wired to either have a common +24V or common 0V / ground connection


Charlie

great result

do you have the option to use 28V bulbs in the switches ?

under run 28V bulbs will last longer


an alternative would be to add a resistor in series with the bulb
if the bulb takes 40 mA a 100 ohm resistor would drop the voltage by 4 V

john