Tiny, honey and nice addon Rated 5 out of 5 stars
But I have few proposals.
1. The checkbox "Let pages override these settings" actually switches off this profile and we can switch between original and only one profile. It would be better to take off this checkbox from options and add to toggling:
Profile1 -> Original -> Profile2 -> Original.
Now we can have dinamically 2 profiles and switch among them.
2. The second proposal is more complex, but more attractive.
To allow to use wallpaper as background (sic!)
I understand, that it is impossible to choose one forground text color for such "mixed" background. But!!! When I highliht some portion of text it gets its "private" background (individually for highlighted portion of text). So, if it is possible to define color for "dedicated for text" background such text will be readable.
If it is possible to have customisable opacity for such "dedicated for text" background, it will not fully hide the wallpaper and simultaneously will allow to read the text.
3. The third proposal is relatively easy. Let assume, that the addon doesn't have two separate parts for profile settings in option menu. It will have only one set of settings, but will include small input field, where user can give a name for chosen setting scheme and save this scheme by this name.
By such way user can have unlimited set of profiles that can be randomly chosen by hot key toggling or CT toggler button in addon bar.
Of course, user should be able to remove some profiles or (in addition) to make them inactive (i.e. they will not participate in random choose).
Such addon will revolve the browser - it will add some "unexpectation" surprising.