I nice testimonials to target/aperture. Both Neptune and Uranus are particularly unforgiving of smaller apertures. Neptune at 350x through my C6 is not at all as nice as through my 8" and at least at 350x in that scope.
Venus Ive learned not to bother with if not for seeing issues than notorious fertile ground for optical illusions. I still look now and again, but its tempered with a lot of respect for its magician like nature.
I'm certain beyond a shadow of a doubt if some one images the number 5 on Venus in photoshop, and pushed it as real - you'd have a line of folks with number 5 drawings of this planet.
Too much going on with me at present so can't get too involved with this. A worthwhile thread which details many of the pitfalls that an experienced observer should constantly address, to the point of it becoming second-nature/automatic.
Venus: what concerns me with some drawings I see of this planet's diaphanous features is when they are executed under reported seeing conditions that can even render Jupiter's features challenging - i.e. such as IV-V seeing! As I have alluded to here: http://alpo-j.asahikawa-med.ac.jp/kk12/v121019z.htm Likewise with Uranus!