I'm fine on my hybrid in street clothes, even jeans, now that I put a saddle on it that fits me. The farthest I've been is about 20 miles, but the limiting factor there is general bike fit, lack of destinations, and disinclination to ride such a heavy bike any farther. I have zero saddle/seam related problems.

My inclination would be to use LESS padding on a saddle I intended to ride in street clothes. The more you give seams the opportunity to sink and dig into your soft parts, the more they will take that opportunity...