I have a stock 2013 DL650 ADV model, with the stock windscreen with laminar lip, hand guards, engine cover, crash bars, bags & trunk.
With this models stock windshield I have no buffeting. I am 5'11" tall with a 30 " inseam. I get wind, but some of that depends on if there is wind blowing, the wind speed and what direction it is from in relation to my direction of travel. I have found that the lower fairing does a really good job of keeping the wind off my lower body, but I haven't experienced any heat issues. The hand guards do direct some wind onto my arms, shoulders and upper torso. More so than the windshield. I have the windshield in its highest position with the longest spacers on the top. I've found that if I'm not riding in any wind, I don't get any wind on me, other than what the hand guards deflect. ( As a point of interest I had hand guards on my 2000 BMW R1100R and ended up taking them off as they actually made the bike colder to ride. It had heated grips so it wasn't an issue ).
So with the above background to answer your question. If the gold wing is giving you 100 % protection than the Vstorm that I ride would give you on average 60-70 %. There is no wind pressure on your chest or helmet. I've always found that heat is the big enemy. We can dress for the cold, but we have trouble dressing for the heat if you are a ATGATT individual and on the road.
Last summer I rode my Harley Softail with a batwing fairing in 100 F + and it was way too hot. I will enjoy the cooler ride from my Vstom.