For breakup at bedroom volume, you're going to have to use the Burn channel. Turn up the Gain(s) and use the Master to control loudness. Don't use the 15 watt Celestion Blue or 50 watt Gold. They are low power speakers, meant to be used in small amps, or in pairs. Sound great, but not meant for big amps.
There are a bunch of Eminence speakers rated at 150 watts. I currently have a Texas Heat (150 watts) in my Mark III (75 watts). Sounds good, tames some of the shrill highs, is designed for early breakup, and weighs half as much as the EVM 12L (10 vs. 20 lbs.).
You simply cannot get a cranked amp tone at quiet levels without either using the Master volume, or an attenuator. Some will argue that pre-amp distortion is not as "good" as a cranked power section, but there's a reason master volume amps have been successful for so long. They work.
As far as Celestion reliability, the only speakers I've blown up in the last twenty years have been world famous Celestions. Yes, I was playing loud. One was a 90 watt Mesa Black Shadow in a 75 watt Mark III amp, the other was an 80 watt in a 100 watt amp.
Your mileage may vary.