Matching tubes at home Q?

[tedmich]

for EL84 microphonics I like the square profile silicone o-rings Dash 211
McMaster Carr 1182N211 $5.62 for a 10 pack
McMaster-Carr

[km6xz]

EL84's have high bulb temperature so I would be a little concerned with putting anything around the bulb that would radiate less heat than the glass, making hot spots. A better but more difficult solutions would be shock-mount sockets and just finding better tubes.