Admittedly, it's been quite a few years since I flew lighties, & furthermore I never had the pleasure of flying the C210. That said, most aircraft flight manuals publish a turbulence penetration speed, & failing that: a manoeuvring speed.
My point being: If the manufacturer publishes a recommended speed, then that's the speed they recommend, so that's the speed you fly. Simple. And with that being said, why bother trying to reinvent the wheel if the manufacturer has already done the math for you? Of course, it will mean having to slow down - which can be frustrating, I know - but them's the breaks. And 'break' you just may if continually ignored, especially with the age & fatigue issues facing so much of the GA fleet these days.