I have have the V:25 10” combo and the full V 90 W head with cab. Now, bedroom volume is a subjective thing but in general, the biggest difference between these two amps is the 90 has an end stage Output control. In this case each channel’s Master level can be set individually and then the final amp level is set by the Output knob. So, it is easy to get a controllable range of volume when playing ‘softly’.
By comparison, the Mark V:25 (and Rectoverb 25) only have channel Masters, there is no end stage Output knob. So, when playing ‘softly’ even a slight, slight nudge on the Master level has a big effect on volume. And, you’ll pretty much be riding 7 o’clock on that Master knob for bedroom volumes (very close to zero level).
So, while it may seem counterintuitive, the big 90 gives more control and tone shaping (Master to output tubes plus end stage Output knob) at bedroom levels than the lower wattage 25. Keep in mind the big 90 can also drop to 10 W like the 25 can also.
At the end of the day, the V:25 still sounds great at bedroom levels but the 90 is a bit more ‘user friendly’ at lower volumes (in my opinion). In both amps the power tubes are not being driven when playing bedroom levels.