The FIKUS adjustable shade works fine at the 50mm setting. There were some labeled for that use, but they show the 35mm setting being for the Summar. I've had no trouble at the 50mm setting. (Of course, the Summar has so much internal vignetting at wide apertures, would you notice more?) It's what I use when the Summar is part of a travel kit.
When not traveling, if I want a shade I use the correct one. Big shades don't bug me.