Missing a detail.. Given the rim width is part of the circle of tire profile state the inside rim width, yours ..
406_47 (marathon +) & I have plenty of side & fork clearance on my Pocket Llama ,, CR 18 rims.. but , Radially, I have to deflate the rear to get it in and out.
worried about being oversize ~Go with the 50 ... get 3, spares are Good things ..