Personal experience with a Chamonix 45N-1 (classic), which has an identical screen to your 45N-2. Today, I could focus and compose with a 105mm f/5.6 in bright daylight using a loupe and the "folding hood with carbon fiber cover". Using my new 90mm f/8, it wasn't too bad to focus, but it was a challenge to compose. A dark cloth (which I thought was in my bag, but wasn't) would have made it no problem. Had I even been in shade, it would have been OK, but at the time, I was in full, bright, Florida sun.

There was also a black snake in the area-- typically non-aggressive, but I'd startled him when I first arrived, and didn't want him sneaking up, so I don't know if I'd have used a darkcloth anyway.

So there is a difference, but overall, the Chamonix screen is pretty bright, and it shouldn't stop you from getting the lens.