Yeah they all say that these days hey...in the 80's it was pretty much a couple of inches taller than yourself & a rhino chaser for the bigger stuff. My normal was my height, 6'1. Then through the 90's from '93 - '99 I lived in Margs & the great ocean road for a couple of years with almost 9 months on the road getting there camping out along the way. My normal board then was 6'8, same one for all those years, a Rick Jacko Alloy Joy.
When considering boards you really need to consider what waves your riding. Sucky waves you want some rocker, fat waves not so much...as you've pointed out you don't want something too wide on bigger waves, its gonna be hard bottom turning...but anyway, without rambling on any further about stuff you probably already know. I think when they say whatever inches shorter than your standard shorty. They're referring to boards with width & volume distribution before the short/wide revolution which I think has been awesome. Then again, I saw an old Hot Brewz on Gumtree last year that I was very tempted to grab which had pretty modern dims. But most boards were what people now term as being matchsticks.
I wouldn't worry too much about the whatever inches shorter than your short board...just consider the kind of waves at your local(s) & what volume is right for you based upon your ability & fitness level...& you can never have too many boards, inform your GF/Wife of this as early as possible
