The cold clipper is on the lead channel, not the crunch channel of the SLO (unless the common schematic out there is wrong - I know you've built a few of these). The clean/crunch just has three "normal" stages on it. While I'd say the SLO crunch and 2203 are in the same general zone for sound, they are definitely voiced a bit differently. That's why I always say they set in the same space but are voiced a bit differently.
I did design a two channel amp that would be similar to a SLO in general layout, and close in topology, back in the 90s based around a 2203 with a lead channel. I never did get around to building it though but have been contemplating doing that over winter break if we aren't leaving town. This thread might push me that way! I would be tempted to put a switchable cold clipper on there.....or at least play around with it a bit while tuning the final circuit in.