I had my ED100 out yesterday night, and managed to split Delta Cygni with relative ease at 150x. So I thought I'd have a go with my FC76 DCU-EX tonight, taking up the challenge with a significantly smaller aperture. It managed to split it clearly in moments of good seeing with my Vixen SLV 6 mm eyepiece (around 159x magnification). The faint companion star was located roughly in the first diffraction ring around the primary star. I was kind of excited because this is the smallest aperture I've successfully used to split this double star, and observing conditions weren't even ideal with fairly high winds and less-than-ideal seeing conditions.
What are your experiences splitting Delta Cygni (2.5" separation, magnitudes 2.9 and 6.3) using smallish apertures?