This is the answer that Evolve gave me when mentioning my concerns about the apparent limitation of certain 50c tires:
Thanks for your message.
Actual tire width may vary depending on the tire brand, model, tread design, rim internal width, tire pressure, and installation conditions. Therefore, 50c tires from some brands work fine on our frameset when fitted to the wheelset. You may refer to the feedback shared by our customer.
However, our recommended tire size is 35–45 mm. To avoid compatibility issues, we still suggest you use tires within this range.
Please feel free to contact us if you have any other questions.
Best regards
A 45mm Hutchinson Toureg Race does fit, I think 5mm at the tightest spot. This is on your 32i rim. This is a pretty big 45c tire, So I'm confident any 45 will fit in the rear.
For 50's, I've seen a report that a Pathfinder 50 will fit, though they run narrow and short, 47mm or so.
The tires that don't fit on a 23.5 innuendo rim:
Schwalbe RXPro 50 (measures 49.8 at 20 psi, used tire), less than 3mm
Schwalbe RPro 50 (measures 49.6 40 psi, new), clearance right at 3mm
Hutchinson Toureg Race 50, 52.2, rubs on one side, less than 2mm other side. Note, Caracal Race is the same dimensions so I'm guessing same result.
Continental Dubnital 50, 49.6, new 40psi, less than 2.75 at the chainstays, this tire is pretty tall.
Looks like they are pretty honest about the 50c clearance but I'm not exactly sure if the Cima Gr is the right frame for me as it looks like my Crux that are rated at 47c had more clearance then this frame that states 50c...not reassuring but at least they are being honest about it when asked directly.