I feel like should give my opinion, as I have been burning my Dauntless without a cat for a couple weeks now, about a dozen burns so far. My stove is a hearth install, 15' oval insulated liner in a masonry chimney, in a room that is almost identical to OP. I've only loaded the firebox a little more than half full, with wood that is 14-18% MC on fresh splits, mainly ash and cherry. Keep in mind, this isn't for heating the whole house, and I will be getting a cat in the near future.
Based on my observations with my set up, this stove likes to be run with the air wide open or close to it with the bypass closed and no cat. I don't actually close the bypass until the STT is at least 550 degrees. Once it's closed, I can cruise at 450-550 with the air wide open for about 3 hours, with single wall pipe temps above 300 before STT start to drop. This produces little smoke out of the chimney, and the glass stays mostly clean, even burning most of the day. I do have to load more frequently, but I rest easy knowing I'm not producing a ton of creosote.
One thing I've learned with this stove that is important, and may help OP, is how and what STT temperature I reload as well as the size of splits. If I try to do a hot reload, with glowing coals, and STT at 500 or higher, there will be a lot of smoke coming out of the chimney once the bypass is closed, especially if I put too much wood in, or too big of splits and don't let it catch and burn a bit before I closed the bypass. If I open the bypass to get the load going, the temps spike pretty quickly and could easily run away if not paying attention. Closing the bypass will get STT under control, but again, things start to smolder until the air regulates. This could take up to 15 minutes or longer before the smoke lessens and the load catches. I can't really turn the primary air down until the load has burned for a good amount of time, even then, there is noticeably more smoke out of the chimney with a hot reload. What I do now is wait until the STT has dropped to under 400, then I'll load the stove, have the primary wide open with the bypass open until STT get to at least 550, ideally a little higher, then I'll close the bypass, keeping the primary wide open for the whole burn or at least an hour before closing it down a little. I cannot imagine closing the air all the way down without a cat, especially after loading the stove completely full with questionable wood MC. Things will just smolder and smolder. I'm looking forward to getting a cat.