You will chase your tail more so on this, than the resistor noise.. picking the right tube for the first preamp of whatever channel of an amp is probably alot more important. Anyone that has built a wreck amp,and went through alot of preamp tubes to find ones with least hiss, least hum or microphonics will know.The general consensus is that your first stage of amplification always sets the signal/noise ratio - unless there's something seriously wrong underway.
BTW - the prices now paid for CCs is a hyped up price, based on limited availability and dubious popularity. 30 years ago, 1/4 W CCs were 5 c's and metal films were 50 cents. Today it's the opposite, also partly based on modern production technology......
To add to that is brand type, and value. Its getting much harder to find certian values,and you'll pay more for those. The brand will also have an impact on how much they go for.. But yeah, use to get them cheap, now the prices have gone way up.