Anyone have experience with either of these on 4x5?

The Compact 350 is a very recent offering from Schneider. But I've never used one of these super-slow lenses before so I'm wondering if it would be essentially impossible to focus under dim lighting or worse, at night. It's a 4-element lens. Sharpness across the entire field? Realistic working aperture? Contrast? Correction?

How about the performance of the 250/5.6?

Thanks