Just another thought to throw into the murky pool...
If you're getting all the top end you need via your "dirty" channel + Schroeder cab, then perhaps the other channel might be better served with one of Alex's Big Sub cabinets. This is, like the Compact, a single 15" cab, but (afaik) uses a different driver more dedicated to low frequencies. Essentially it's the Big One without the midrange driver.
For your purposes, I would guess that the differences from the Compact might be the following:
CONs:
- Marginally more expensive (£450 rather than £400, according to the website)
- I don't think he's actually made any of them yet!
PROs:
- Deeper bottom end
- May also possibly solve your aesthetic issue with stacking the deeper Schroeder (16") on top of the shallower Compact (13.5")
Not certain on this as there's no dimensions for the Big Sub on the website, but I'm guessing that, as part of the "Big" series, it may share the 16" depth of the Big One...?
Don't know about its height, but possibly, without the midrange section of the Big One, it might be a similar height to the Compact (25.5")...?
So, stacked on its side with the Schroeder (23.5"). this might work ok...?
Disclaimer: this stuff about dimensions is really just guesswork; I'll have to rely on Alex correcting anything that's wildly wrong!
cheers