Sounds like you think we're doing science here. The OP's questions made me think he was entertaining ideas along the lines of kluges or non-standard field repairs.

Whether a bike will fit the width of tire you want to use is one of the bigger parameters affecting the bike's utility or excellence for the stated purpose. OP has stated that he's willing to try something even if there's a chance it may break down the road. I understand the feeling; rather than ride a bike with a too-small rear tire, I'd be inclined to either try something dodgy or get rid of that frame and get something more suitable.

He asked folks here for advice and I gave him some, with a few words about my experience level because I assumed he would be curious what I'm basing that on. To call that arguing from authority seems a bit high-falutin' for this discussion. Still, congratulations on your win.