I would recommend a Weber Mass attenuator. They work great.
As for tone loss, IMO, you won't lose much. Will you be able to tell a difference? Yes, maybe. But, I look at it as less a matter of 'tone loss' and more of 'tone difference' that can be adjusted, for the most part, with your eq. Along with the comment about pedals, I'm one to wonder how much it matters if you do lose some tone if you're just practicing in your bedroom/small room at home?
As it is, your sound isn't to your liking because it's too loud. 'Losing tone' may be a great trade-off for a tone you can actually work with.
This comment isn't to the op, since he already has his setup. I agree with the pedal comment, to the extent that when volume matters as much as it does for people practicing at home or in apartments, setting up a rig with pedals and a clean amp really is the way to go, IMO.
Your results may vary.